essay on nutrition in plants

• Biology Article

Nutrition In Plants

Nutrients are the components found in our food such as carbohydrates, vitamins, minerals, fats, etc. These components are necessary for living organisms to survive. Plants produce their own food while animals and human beings do not produce their own food. We indirectly or directly depend on plants and animals for our food needs.

Table of Contents

Photosynthesis

Conditions necessary for photosynthesis, steps in photosynthesis, parasitic nutrition, insectivorous nutrition, saprophytic nutrition, symbiotic nutrition, modes of nutrition.

The process of obtaining food and utilizing it to grow, stay healthy and repair any damaged body part is known as nutrition. Plants produce their food by taking raw materials from their surroundings, such as minerals, carbon dioxide, water and sunlight. There are two modes of nutrition:

• Autotrophic – Plants exhibit autotrophic nutrition and are called primary producers. Plants synthesis their food by using light, carbon dioxide and water.
• Heterotrophic – Both animals and human beings are called heterotrophs, as they depend on plants for their food.

Also Refer: Different Modes Of Nutrition in Living Organisms

Recommended Video:

Autotrophic Nutrition in Plants

Plants are able to produce their own food through a process called photosynthesis.

The chloroplast is the site of photosynthesis.

Food production primarily is carried out in leaves. Water and minerals from the soil are absorbed by the root and transported to the leaves through vessels. Carbon dioxide reaches leaves through stomata – which are small pores on leaves surrounded by guard cells.

Chlorophyll is a green pigment present in leaves which helps the leaves capture energy from sunlight to prepare their food. This production of food which takes place in the presence of sunlight is known as photosynthesis. Hence, the sun serves as the primary source for all living organisms

During photosynthesis, water and carbon dioxide are used in the presence of sunlight to produce carbohydrates and oxygen.

Photosynthesis provides food to all living beings.

Oxygen, one of the main components of life on earth is released by plants during photosynthesis.

Also Refer: Photosynthesis

Carbon dioxide

Chlorophyll

Absorption of energy from sunlight

Conversion of light energy into chemical energy

Hydrolysis of water into oxygen and hydrogen

Carbon dioxide is reduced to form glucose by utilizing chemical energy

Also Read:  Nutrition in Animals

Heterotrophic Nutrition in Plants

Some plants do not contain chlorophyll and depend on other plants for their food through the heterotrophic mode of nutrition. These type of nutrition in plants are referred to as  Heterotrophic nutrition   in plants, hence are called parasites.

Heterotrophic Plants

Listed below are different types of heterotrophic plants that are mainly classified based on their mode of nutrition:

Insectivorous

Saprophytic

Some heterotrophic plants depend on other plants and animals for nutrition. Such plants are known as parasitic plants. However, the host is not benefitted from the parasite.

For eg., Cuscuta, Cassytha

Also Read:   Parasitism

Some plants have special structural features that help them to trap insects and are commonly known as carnivorous or heterotrophic plants. These plants digest the insects by secreting digestive juices and absorb the nutrients from them. These plants grow on the soil that lacks minerals.

For eg., Pitcher plant, Venus flytrap

Also Read:  Insectivorous Plants

The saprophytic plants derive nutrition from dead and decaying plants and animals. They dissolve the dead and decaying matter by secreting digestive juices and absorb the nutrients.

For eg., mushrooms, moulds.

Also Read:  Saprophytes

When two different plants belonging to two different categories show a close association, they are termed as symbiotic. In this, both the plants are benefitted from each other.

For eg., the association of fungi and trees.

Also Read: Mutualism

Learn more in detail about Nutrition in Plants, Heterotrophic Plants or any other related topics at  BYJU’S Biology

Frequently Asked Questions

What is plant nutrition.

Plant nutrition is the study of elements and compounds necessary for plant growth, metabolism and external supply. A plant cannot complete its life cycle in its absence.

What is the main mode of nutrition in plants?

The main mode of nutrition in plants is the autotrophic mode of nutrition. Plants have chlorophyll in their leaves which helps them to produce their own food.

What are the different types of heterotrophic nutrition in plants?

Some plants do not have chlorophyll and depend upon other plants for their food. Such plants exhibit a heterotrophic mode of nutrition and are known as heterotrophic plants. For eg., parasitic plants, insectivorous plants, symbiotic plants and saprophytic plants.

What are insectivorous plants?

Insectivorous plants are the plants that trap insects. Their leaves are modified into special structures which traps the insects and digest it with the help of digestive enzymes to derive nutrition from them.

What are the important nutrients required by the plants?

Plants require two types of nutrients- macronutrients and micronutrients. Macronutrients include nitrogen, phosphorus, potassium, calcium, magnesium and sulphur. The micronutrients include boron, chlorine, copper, iron, manganese, molybdenum, and zinc.

How are the nutrients absorbed by the plants?

Plants absorb nutrients through their roots. They transport nutrients and water up through the stem to the parts that are above ground level.

Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin!

Select the correct answer and click on the “Finish” button Check your score and answers at the end of the quiz

Visit BYJU’S for all Biology related queries and study materials

Your result is as below

Request OTP on Voice Call

Leave a Comment Cancel reply

Your Mobile number and Email id will not be published. Required fields are marked *

Post My Comment

thanks for learning

So helpful. Thank you

So easy to learn

so helpful and thanks

SO HELPFUL FOR US thank you so much

So helpful thank u so much

Very helpful thank you byjus

It is so helpful

Thank you very much today is my seminar this is very easy to learn once again thank you soo much

Wow thanks a lot this will really help with my presentation.

Register with BYJU'S & Download Free PDFs

Register with byju's & watch live videos.

• school Campus Bookshelves
• menu_book Bookshelves
• perm_media Learning Objects
• login Login
• how_to_reg Request Instructor Account
• hub Instructor Commons

Margin Size

• Download Page (PDF)
• Download Full Book (PDF)
• Periodic Table
• Physics Constants
• Scientific Calculator
• Reference & Cite
• Tools expand_more
• Readability

selected template will load here

This action is not available.

31.1C: Essential Nutrients for Plants

• Last updated
• Save as PDF
• Page ID 13781

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

\( \newcommand{\Span}{\mathrm{span}}\)

\( \newcommand{\id}{\mathrm{id}}\)

\( \newcommand{\kernel}{\mathrm{null}\,}\)

\( \newcommand{\range}{\mathrm{range}\,}\)

\( \newcommand{\RealPart}{\mathrm{Re}}\)

\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

\( \newcommand{\Argument}{\mathrm{Arg}}\)

\( \newcommand{\norm}[1]{\| #1 \|}\)

\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

\( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

\( \newcommand{\vectorC}[1]{\textbf{#1}} \)

\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

Approximately 20 macronutrients and micronutrients are deemed essential nutrients to support all the biochemical needs of plants.

Learning Objectives

• Distinguish among the essential nutrients for plants
• An element is essential if a plant cannot complete its life cycle without it, if no other element can perform the same function, and if it is directly involved in nutrition.
• An essential nutrient required by the plant in large amounts is called a macronutrient, while one required in very small amounts is termed a micronutrient.
• Missing or inadequate supplies of nutrients adversely affect plant growth, leading to stunted growth, slow growth, chlorosis, or cell death.
• About half the essential nutrients are micronutrients such as boron, chlorine, manganese, iron, zinc, copper, molybdenum, nickel, silicon, and sodium.
• micronutrient : a mineral, vitamin, or other substance that is essential, even in very small quantities, for growth or metabolism
• chlorosis : a yellowing of plant tissue due to loss or absence of chlorophyll
• macronutrient : any of the elements required in large amounts by all living things

Essential Nutrients

Plants require only light, water, and about 20 elements to support all their biochemical needs. These 20 elements are called essential nutrients. For an element to be regarded as essential, three criteria are required:

• a plant cannot complete its life cycle without the element
• no other element can perform the function of the element
• the element is directly involved in plant nutrition

Macronutrients and Micronutrients

The essential elements can be divided into macronutrients and micronutrients. Nutrients that plants require in larger amounts are called macronutrients. About half of the essential elements are considered macronutrients: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. The first of these macronutrients, carbon (C), is required to form carbohydrates, proteins, nucleic acids, and many other compounds; it is, therefore, present in all macromolecules. On average, the dry weight (excluding water) of a cell is 50 percent carbon, making it a key part of plant biomolecules.

The next-most-abundant element in plant cells is nitrogen (N); it is part of proteins and nucleic acids. Nitrogen is also used in the synthesis of some vitamins. Hydrogen and oxygen are macronutrients that are part of many organic compounds and also form water. Oxygen is necessary for cellular respiration; plants use oxygen to store energy in the form of ATP. Phosphorus (P), another macromolecule, is necessary to synthesize nucleic acids and phospholipids. As part of ATP, phosphorus enables food energy to be converted into chemical energy through oxidative phosphorylation. Light energy is converted into chemical energy during photophosphorylation in photosynthesis; and into chemical energy to be extracted during respiration. Sulfur is part of certain amino acids, such as cysteine and methionine, and is present in several coenzymes. Sulfur also plays a role in photosynthesis as part of the electron transport chain where hydrogen gradients are key in the conversion of light energy into ATP. Potassium (K) is important because of its role in regulating stomatal opening and closing. As the openings for gas exchange, stomata help maintain a healthy water balance; a potassium ion pump supports this process.

Magnesium (Mg) and calcium (Ca) are also important macronutrients. The role of calcium is twofold: to regulate nutrient transport and to support many enzyme functions. Magnesium is important to the photosynthetic process. These minerals, along with the micronutrients, also contribute to the plant’s ionic balance.

In addition to macronutrients, organisms require various elements in small amounts. These micronutrients, or trace elements, are present in very small quantities. The seven main micronutrients include boron, chlorine, manganese, iron, zinc, copper, and molybdenum. Boron (B) is believed to be involved in carbohydrate transport in plants; it also assists in metabolic regulation. Boron deficiency will often result in bud dieback. Chlorine (Cl) is necessary for osmosis and ionic balance; it also plays a role in photosynthesis. Copper (Cu) is a component of some enzymes. Symptoms of copper deficiency include browning of leaf tips and chlorosis (yellowing of the leaves). Iron (Fe) is essential for chlorophyll synthesis, which is why an iron deficiency results in chlorosis. Manganese (Mn) activates some important enzymes involved in chlorophyll formation. Manganese-deficient plants will develop chlorosis between the veins of its leaves. The availability of manganese is partially dependent on soil pH. Molybdenum (Mo) is essential to plant health as it is used by plants to reduce nitrates into usable forms. Some plants use it for nitrogen fixation; thus, it may need to be added to some soils before seeding legumes. Zinc (Zn) participates in chlorophyll formation and also activates many enzymes. Symptoms of zinc deficiency include chlorosis and stunted growth.

Deficiencies in any of these nutrients, particularly the macronutrients, can adversely affect plant growth. Depending on the specific nutrient, a lack can cause stunted growth, slow growth, or chlorosis. Extreme deficiencies may result in leaves showing signs of cell death.

Contributions and Attributions

• OpenStax College, Biology. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44712/latest...ol11448/latest . License : CC BY: Attribution
• OpenStax College, Biology. November 22, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44714/latest...ol11448/latest . License : CC BY: Attribution
• photosynthesis. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/photosynthesis . License : CC BY-SA: Attribution-ShareAlike
• nutrient. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/nutrient . License : CC BY-SA: Attribution-ShareAlike
• germinate. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/germinate . License : CC BY-SA: Attribution-ShareAlike
• OpenStax College, Introduction. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44712/latest...31_00_01ab.jpg . License : CC BY: Attribution
• transpiration. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/transpiration . License : CC BY-SA: Attribution-ShareAlike
• OpenStax College, Biology. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44714/latest...ol11448/latest . License : CC BY: Attribution
• xylem. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/xylem . License : CC BY-SA: Attribution-ShareAlike
• organic. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/organic . License : CC BY-SA: Attribution-ShareAlike
• inorganic. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/inorganic . License : CC BY-SA: Attribution-ShareAlike
• OpenStax College, Nutritional Requirements of Plants. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44714/latest...e_31_01_01.jpg . License : CC BY: Attribution
• Micronutrient. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Micronutrient . License : CC BY-SA: Attribution-ShareAlike
• chlorosis. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/chlorosis . License : CC BY-SA: Attribution-ShareAlike
• micronutrient. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/micronutrient . License : CC BY-SA: Attribution-ShareAlike
• macronutrient. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/macronutrient . License : CC BY-SA: Attribution-ShareAlike
• OpenStax College, Nutritional Requirements of Plants. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44714/latest/Figure_31_01_03abcd.jpg . License : CC BY: Attribution

Module 8: Plant Structure and Function

Plant nutrition, discuss the common nutritional needs of plants.

Plants obtain food in two different ways. Autotrophic plants can make their own food from inorganic raw materials, such as carbon dioxide and water, through photosynthesis in the presence of sunlight. Green plants are included in this group. Some plants, however, are heterotrophic: they are totally parasitic and lacking in chlorophyll. These plants, referred to as holo-parasitic plants, are unable to synthesize organic carbon and draw all of their nutrients from the host plant.

Plants may also enlist the help of microbial partners in nutrient acquisition. Particular species of bacteria and fungi have evolved along with certain plants to create a mutualistic symbiotic relationship with roots. This improves the nutrition of both the plant and the microbe. The formation of nodules in legume plants and mycorrhization can be considered among the nutritional adaptations of plants. However, these are not the only type of adaptations that we may find; many plants have other adaptations that allow them to thrive under specific conditions.

Learning Objectives

• List the elements and compounds required for proper plant nutrition
• Describe how symbiotic relationships help autotrophic plants obtain nutrients
• Describe how heterotrophic plants obtain nutrients

Nutritional Requirements

Plants are unique organisms that can absorb nutrients and water through their root system, as well as carbon dioxide from the atmosphere. Soil quality and climate are the major determinants of plant distribution and growth. The combination of soil nutrients, water, and carbon dioxide, along with sunlight, allows plants to grow.

The Chemical Composition of Plants

Figure 1. Water is absorbed through the root hairs and moves up the xylem to the leaves.

Since plants require nutrients in the form of elements such as carbon and potassium, it is important to understand the chemical composition of plants. The majority of volume in a plant cell is water; it typically comprises 80 to 90 percent of the plant’s total weight. Soil is the water source for land plants, and can be an abundant source of water, even if it appears dry. Plant roots absorb water from the soil through root hairs and transport it up to the leaves through the xylem. As water vapor is lost from the leaves, the process of transpiration and the polarity of water molecules (which enables them to form hydrogen bonds) draws more water from the roots up through the plant to the leaves (Figure 1). Plants need water to support cell structure, for metabolic functions, to carry nutrients, and for photosynthesis.

Plant cells need essential substances, collectively called nutrients, to sustain life. Plant nutrients may be composed of either organic or inorganic compounds. An organic compound is a chemical compound that contains carbon, such as carbon dioxide obtained from the atmosphere. Carbon that was obtained from atmospheric CO 2 composes the majority of the dry mass within most plants. An inorganic compound does not contain carbon and is not part of, or produced by, a living organism. Inorganic substances, which form the majority of the soil solution, are commonly called minerals: those required by plants include nitrogen (N) and potassium (K) for structure and regulation.

Essential Nutrients

Plants require only light, water and about 20 elements to support all their biochemical needs: these 20 elements are called essential nutrients (Table 1). For an element to be regarded as essential , three criteria are required: 1) a plant cannot complete its life cycle without the element; 2) no other element can perform the function of the element; and 3) the element is directly involved in plant nutrition.

Macronutrients and Micronutrients

The essential elements can be divided into two groups: macronutrients and micronutrients. Nutrients that plants require in larger amounts are called macronutrients . About half of the essential elements are considered macronutrients: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. The first of these macronutrients, carbon (C), is required to form carbohydrates, proteins, nucleic acids, and many other compounds; it is therefore present in all macromolecules. On average, the dry weight (excluding water) of a cell is 50 percent carbon. As shown in Figure 2, carbon is a key part of plant biomolecules.

Figure 2. Cellulose, the main structural component of the plant cell wall, makes up over thirty percent of plant matter. It is the most abundant organic compound on earth.

The next most abundant element in plant cells is nitrogen (N); it is part of proteins and nucleic acids. Nitrogen is also used in the synthesis of some vitamins. Hydrogen and oxygen are macronutrients that are part of many organic compounds, and also form water. Oxygen is necessary for cellular respiration; plants use oxygen to store energy in the form of ATP. Phosphorus (P), another macromolecule, is necessary to synthesize nucleic acids and phospholipids. As part of ATP, phosphorus enables food energy to be converted into chemical energy through oxidative phosphorylation. Likewise, light energy is converted into chemical energy during photophosphorylation in photosynthesis, and into chemical energy to be extracted during respiration. Sulfur is part of certain amino acids, such as cysteine and methionine, and is present in several coenzymes. Sulfur also plays a role in photosynthesis as part of the electron transport chain, where hydrogen gradients play a key role in the conversion of light energy into ATP. Potassium (K) is important because of its role in regulating stomatal opening and closing. As the openings for gas exchange, stomata help maintain a healthy water balance; a potassium ion pump supports this process.

Magnesium (Mg) and calcium (Ca) are also important macronutrients. The role of calcium is twofold: to regulate nutrient transport, and to support many enzyme functions. Magnesium is important to the photosynthetic process. These minerals, along with the micronutrients, which are described below, also contribute to the plant’s ionic balance.

In addition to macronutrients, organisms require various elements in small amounts. These micronutrients , or trace elements, are present in very small quantities. They include boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni), silicon (Si), and sodium (Na).

Figure 3. Nutrient deficiency is evident in the symptoms these plants show. This (a) grape tomato suffers from blossom end rot caused by calcium deficiency. The yellowing in this (b) Frangula alnus results from magnesium deficiency. Inadequate magnesium also leads to (c) intervenal chlorosis, seen here in a sweetgum leaf. This (d) palm is affected by potassium deficiency. (credit c: modification of work by Jim Conrad; credit d: modification of work by Malcolm Manners)

Deficiencies in any of these nutrients—particularly the macronutrients—can adversely affect plant growth (Figure 3). Depending on the specific nutrient, a lack can cause stunted growth, slow growth, or chlorosis (yellowing of the leaves). Extreme deficiencies may result in leaves showing signs of cell death.

Hydroponics

Hydroponics is a method of growing plants in a water-nutrient solution instead of soil. Since its advent, hydroponics has developed into a growing process that researchers often use. Scientists who are interested in studying plant nutrient deficiencies can use hydroponics to study the effects of different nutrient combinations under strictly controlled conditions. Hydroponics has also developed as a way to grow flowers, vegetables, and other crops in greenhouse environments. You might find hydroponically grown produce at your local grocery store. Today, many lettuces and tomatoes in your market have been hydroponically grown.

In Summary: Nutritional Requirements

Plants can absorb inorganic nutrients and water through their root system, and carbon dioxide from the environment. The combination of organic compounds, along with water, carbon dioxide, and sunlight, produce the energy that allows plants to grow. Inorganic compounds form the majority of the soil solution. Plants access water though the soil. Water is absorbed by the plant root, transports nutrients throughout the plant, and maintains the structure of the plant. Essential elements are indispensable elements for plant growth. They are divided into macronutrients and micronutrients. The macronutrients plants require are carbon, nitrogen, hydrogen, oxygen, phosphorus, potassium, calcium, magnesium, and sulfur. Important micronutrients include iron, manganese, boron, molybdenum, copper, zinc, chlorine, nickel, cobalt, silicon and sodium.

Autotrophic Plants

Nitrogen fixation: root and bacteria interactions.

Nitrogen is an important macronutrient because it is part of nucleic acids and proteins. Atmospheric nitrogen, which is the diatomic molecule N 2 , or dinitrogen, is the largest pool of nitrogen in terrestrial ecosystems. However, plants cannot take advantage of this nitrogen because they do not have the necessary enzymes to convert it into biologically useful forms. However, nitrogen can be “fixed,” which means that it can be converted to ammonia (NH 3 ) through biological, physical, or chemical processes. As you have learned, biological nitrogen fixation (BNF) is the conversion of atmospheric nitrogen (N 2 ) into ammonia (NH 3 ), exclusively carried out by prokaryotes such as soil bacteria or cyanobacteria. Biological processes contribute 65 percent of the nitrogen used in agriculture. The following equation represents the process:

[latex]\text{N}_2+16\text{ ATP}+8\text{e}^{-}+8\text{H}^{+}\longrightarrow2\text{NH}_{3}+16\text{ ADP}+16\text{Pi}+\text{H}_2[/latex]

The most important source of BNF is the symbiotic interaction between soil bacteria and legume plants, including many crops important to humans (Figure 4). The NH3 resulting from fixation can be transported into plant tissue and incorporated into amino acids, which are then made into plant proteins. Some legume seeds, such as soybeans and peanuts, contain high levels of protein, and serve among the most important agricultural sources of protein in the world.

Figure 4. Some common edible legumes—like (a) peanuts, (b) beans, and (c) chickpeas—are able to interact symbiotically with soil bacteria that fix nitrogen. (credit a: modification of work by Jules Clancy; credit b: modification of work by USDA)

Practice Question

Farmers often rotate corn (a cereal crop) and soy beans (a legume), planting a field with each crop in alternate seasons. What advantage might this crop rotation confer?

Soil bacteria, collectively called rhizobia , symbiotically interact with legume roots to form specialized structures called nodules , in which nitrogen fixation takes place. This process entails the reduction of atmospheric nitrogen to ammonia, by means of the enzyme nitrogenase . Therefore, using rhizobia is a natural and environmentally friendly way to fertilize plants, as opposed to chemical fertilization that uses a nonrenewable resource, such as natural gas. Through symbiotic nitrogen fixation, the plant benefits from using an endless source of nitrogen from the atmosphere. The process simultaneously contributes to soil fertility because the plant root system leaves behind some of the biologically available nitrogen. As in any symbiosis, both organisms benefit from the interaction: the plant obtains ammonia, and bacteria obtain carbon compounds generated through photosynthesis, as well as a protected niche in which to grow (Figure 5).

Figure 5. Soybean roots contain (a) nitrogen-fixing nodules. Cells within the nodules are infected with Bradyrhyzobium japonicum , a rhizobia or “root-loving” bacterium. The bacteria are encased in (b) vesicles inside the cell, as can be seen in this transmission electron micrograph. (credit a: modification of work by USDA; credit b: modification of work by Louisa Howard, Dartmouth Electron Microscope Facility; scale-bar data from Matt Russell)

Mycorrhizae: The Symbiotic Relationship between Fungi and Roots

A nutrient depletion zone can develop when there is rapid soil solution uptake, low nutrient concentration, low diffusion rate, or low soil moisture. These conditions are very common; therefore, most plants rely on fungi to facilitate the uptake of minerals from the soil. Fungi form symbiotic associations called mycorrhizae with plant roots, in which the fungi actually are integrated into the physical structure of the root. The fungi colonize the living root tissue during active plant growth.

Figure 6. Root tips proliferate in the presence of mycorrhizal infection, which appears as off-white fuzz in this image. (credit: modification of work by Nilsson et al., BMC Bioinformatics 2005)

Through mycorrhization, the plant obtains mainly phosphate and other minerals, such as zinc and copper, from the soil. The fungus obtains nutrients, such as sugars, from the plant root (Figure 6). Mycorrhizae help increase the surface area of the plant root system because hyphae, which are narrow, can spread beyond the nutrient depletion zone. Hyphae can grow into small soil pores that allow access to phosphorus that would otherwise be unavailable to the plant. The beneficial effect on the plant is best observed in poor soils. The benefit to fungi is that they can obtain up to 20 percent of the total carbon accessed by plants. Mycorrhizae functions as a physical barrier to pathogens. It also provides an induction of generalized host defense mechanisms, and sometimes involves production of antibiotic compounds by the fungi.

There are two types of mycorrhizae: ectomycorrhizae and endomycorrhizae. Ectomycorrhizae form an extensive dense sheath around the roots, called a mantle. Hyphae from the fungi extend from the mantle into the soil, which increases the surface area for water and mineral absorption. This type of mycorrhizae is found in forest trees, especially conifers, birches, and oaks. Endomycorrhizae, also called arbuscular mycorrhizae, do not form a dense sheath over the root. Instead, the fungal mycelium is embedded within the root tissue. Endomycorrhizae are found in the roots of more than 80 percent of terrestrial plants.

Heterotrophic Plants

Some plants cannot produce their own food and must obtain their nutrition from outside sources—these plants are heterotrophic. This may occur with plants that are parasitic or saprophytic. Some plants are mutualistic symbionts, epiphytes, or insectivorous.

Plant Parasites

A parasitic plant depends on its host for survival. Some parasitic plants have no leaves. An example of this is the dodder (Figure 7a), which has a weak, cylindrical stem that coils around the host and forms suckers. From these suckers, cells invade the host stem and grow to connect with the vascular bundles of the host. The parasitic plant obtains water and nutrients through these connections. The plant is a total parasite (a holoparasite) because it is completely dependent on its host. Other parasitic plants (hemiparasites) are fully photosynthetic and only use the host for water and minerals. There are about 4,100 species of parasitic plants.

Saprophytes

A saprophyte is a plant that does not have chlorophyll and gets its food from dead matter, similar to bacteria and fungi (note that fungi are often called saprophytes, which is incorrect, because fungi are not plants). Plants like these use enzymes to convert organic food materials into simpler forms from which they can absorb nutrients (Figure 7b). Most saprophytes do not directly digest dead matter: instead, they parasitize fungi that digest dead matter, or are mycorrhizal, ultimately obtaining photosynthate from a fungus that derived photosynthate from its host. Saprophytic plants are uncommon; only a few species are described.

Figure 7. (a) The dodder is a holoparasite that penetrates the host’s vascular tissue and diverts nutrients for its own growth. Note that the vines of the dodder, which has white flowers, are beige. The dodder has no chlorophyll and cannot produce its own food. (b) Saprophytes, like this Dutchmen’s pipe ( Monotropa hypopitys ), obtain their food from dead matter and do not have chlorophyll. (a credit: “Lalithamba”/Flickr; b credit: modification of work by Iwona Erskine-Kellie)

A symbiont is a plant in a symbiotic relationship, with special adaptations such as mycorrhizae or nodule formation. Fungi also form symbiotic associations with cyanobacteria and green algae (called lichens). Lichens can sometimes be seen as colorful growths on the surface of rocks and trees (Figure 8a). The algal partner (phycobiont) makes food autotrophically, some of which it shares with the fungus; the fungal partner (mycobiont) absorbs water and minerals from the environment, which are made available to the green alga. If one partner was separated from the other, they would both die.

An epiphyte is a plant that grows on other plants, but is not dependent upon the other plant for nutrition (Figure 8b). Epiphytes have two types of roots: clinging aerial roots, which absorb nutrients from humus that accumulates in the crevices of trees; and aerial roots, which absorb moisture from the atmosphere.

Figure 8. (a) Lichens, which often have symbiotic relationships with other plants, can sometimes be found growing on trees. (b) These epiphyte plants grow in the main greenhouse of the Jardin des Plantes in Paris. (credit: a “benketaro”/Flickr)

Insectivorous Plants

Figure 9. A Venus flytrap has specialized leaves to trap insects. (credit: “Selena N. B. H.”/Flickr)

An insectivorous plant has specialized leaves to attract and digest insects. The Venus flytrap is popularly known for its insectivorous mode of nutrition, and has leaves that work as traps (Figure 9).

The minerals it obtains from prey compensate for those lacking in the boggy (low pH) soil of its native North Carolina coastal plains. There are three sensitive hairs in the center of each half of each leaf. The edges of each leaf are covered with long spines. Nectar secreted by the plant attracts flies to the leaf. When a fly touches the sensory hairs, the leaf immediately closes. Next, fluids and enzymes break down the prey and minerals are absorbed by the leaf. Since this plant is popular in the horticultural trade, it is threatened in its original habitat.

Check Your Understanding

Answer the question(s) below to see how well you understand the topics covered in the previous section. This short quiz does  not  count toward your grade in the class, and you can retake it an unlimited number of times.

Use this quiz to check your understanding and decide whether to (1) study the previous section further or (2) move on to the next section.

• Introduction to Plant Nutrition. Authored by : Shelli Carter and Lumen Learning. Provided by : Lumen Learning. License : CC BY: Attribution
• Biology. Provided by : OpenStax CNX. Located at : http://cnx.org/contents/[email protected] . License : CC BY: Attribution . License Terms : Download for free at http://cnx.org/contents/[email protected]

Introduction to Plant Nutrition

• First Online: 13 July 2021

Cite this chapter

• Renato de Mello Prado 2  

1163 Accesses

3 Citations

The introduction to plant nutrition addresses basic and general topics on the importance of this area to meet nutritional requirements and promote crop growth, development, and yield. We will address important topics, such as (1) concepts of plant nutrition and its relationship with related disciplines; (2) the concept of nutrient and criteria of essentiality; (3) relative composition of nutrients in plants; (4) nutrient accumulation by crops and crop formation; (5) other chemical elements of interest in plant nutrition, such as potentially toxic and beneficial elements, with emphasis on silicon; and (6) hydroponic cultivation, preparation, and use of nutritional solutions.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

• Available as EPUB and PDF
• Read on any device
• Instant download
• Own it forever
• Compact, lightweight edition
• Dispatched in 3 to 5 business days
• Free shipping worldwide - see info
• Durable hardcover edition

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Alonso TAS, Barreto RF, Prado RM, et al. Silicon spraying alleviates calcium deficiency in tomato plants, but ca-EDTA is toxic. J Plant Nutr Soil Sci. 2020;183:659–64. https://doi.org/10.1002/jpln.202000055 .

Article   CAS   Google Scholar  

Alvarez RCF, Prado RM, Felisberto G, et al. Effects of soluble silicate and nanosilica applied to oxisol on rice nutrition. Pedosphere. 2018;28:597–606. https://doi.org/10.1016/S1002-0160(18)60035-9 .

Article   Google Scholar  

Alves BJR, Santos JCF, Virgem Filho AC, et al. Avaliação da disponibilidade de macro e micronutrientes para arroz de sequeiro cultivado em um solo calcário da região de Irece, Bahia. Revista Universidade Rural. 2002;22:15–24.

Google Scholar  

Alves AU, Prado RM, Gondim ARO, et al. Effect of macronutrient omission on beet development and nutritional status. Hortic Bras. 2008;26:282–5.

Alves RC, Nicolau MCM, Checchio MV, et al. Salt stress alleviation by seed priming with silicon in lettuce seedlings: an approach based on enhancing antioxidant responses. Bragantia. 2020;79:19–29. https://doi.org/10.1590/1678-4499.20190360 .

Amaral DW, Deficiências de macronutrientes e de boro em seringueira (Hevea brasiliensis L.). Dissertação, Escola Superior de Agricultura Luiz de Queiroz. 1983.

Avilán LR. Efectos de la deficiencia de macronutrientes sobre el crecimiento y la composicion quimica de la parcha granadina (Passiflora quadrangularis L.) cultivada en soluciones nutritivas. Agronomía Tropical. 1974;24:133–40.

Avilán LR. Efecto de la omisión de los macronutrientes en el desarollo y composición química de la guanábana (Annona muricata L.) cultivada en soluciones nutritivas. Agronomia Tropical. 1975;25:73–9.

Backes FAAL, Santos OSS, Pila FG, et al. Nutrients replacement in nutrient solution for lettuce hydroponic cultivation. Ciênc Rural. 2004;34:1407–14. https://doi.org/10.1590/S0103-84782004000500013 .

Barreto RF, Prado RM, Leal AJF, et al. Mitigation of ammonium toxicity by silicon in tomato depends on the ammonicum concentration. Acta Agric Scand B Soil Plant Sci. 2016;66:483–8. https://doi.org/10.1080/09064710.2016.1178324 .

Barreto RF, Prad RM, Schiavon Júnior PA, et al. Silicon alleviates ammonium toxicity in cauliflower and in broccoli. Sci Hortic. 2017;225:743–50. https://doi.org/10.1016/j.scienta.2017.08.014 .

Barreto RF, Prado RM, Habermann E, et al. Warming change nutritional status and improve Stylosanthes capitata Vogel growth only under well-watered conditions. J Soil Sci Plant Nutr. 2020;20:00255. https://doi.org/10.1007/s42729-020-00255-5 .

Barroso DG, Figueiredo FAMMA, Pereira RC, et al. Diagnóstico de deficiência de macronutrientes em mudas de teca. Rev Árvore. 2005;29:671–9. https://doi.org/10.1590/S0100-67622005000500002 .

Bataglia OC, Mascarenhas HAA. Absorção de nutrientes pela soja. Campinas: Instituto Agronômico; 1977.

Batista MMF, Viégas IJM, Frazão DAC, et al. Effect of macronutrient omission in growth, symptoms of nutricional deficiency and mineral composition in soursop plants ( Annona muricata ). Rev Bras Frutic. 2003;25:315–8. https://doi.org/10.1590/S0100-29452003000200033 .

Borges BMMN, Flores RA, Almeida HJ, et al. Macronutrient omission and the development and nutritional status of basil in nutritive solution. J Plant Nutr. 2016;39:1627–33. https://doi.org/10.1080/01904167.2016.1187742 .

Braccini MCL, Martinez HEP, Braccini AL, et al. Rhizosphere pH evaluation of coffee genotypes in response to soil aluminum toxicity. Bragantia. 2000;59:83–8. https://doi.org/10.1590/S0006-87052000000100013 .

Browne CA. Liebig and the law of the minimum. In: Moulton FR, editor. Liebig and after Liebig: a century of progress in agricultural chemistry. Washington, DC: American Association for the Advancement of Science; 1942. p. 71–82.

Brownell PF, Bielig LM. The role of sodium in the conversion of pyruvate to phosphoenolpyruvate in mesophyll chloroplasts of C4 plants. Aust J Plant Physiol. 1996;23:171–7. https://doi.org/10.1071/PP9960171 .

Brownell PF, Wood JG. Sodium as an essential micronutrient element for Atriplex vesicaria, Heward. Nature. 1957;179:635–6. https://doi.org/10.1038/179635a0 .

Buchelt AC, Teixeira GCM, Oliveira KS, et al. Silicon contribution via nutrient solution in forage plants to mitigate nitrogen, potassium, calcium, magnesium, and sulfur deficiency. J Soil Sci Plant Nutr. 2020;20:1532–48. https://doi.org/10.1007/s42729-020-00245-7 .

Bugbee B. Nutrient management in recirculanting hydroponic culture. In: Abstracts of the 16rd annual conference on hydroponics. Tucson: Hydroponic Society of America; 1995. p. 15.

Calero Hurtado A, Chiconato DA, Prado RM, et al. Silicon attenuates sodium toxicity by improving nutritional efficiency in sorghum and sunflower plants. Plant Physiol Biochem. 2019;142:224–33. https://doi.org/10.1016/j.plaphy.2019.07.010 .

Article   CAS   PubMed   Google Scholar  

Calero Hurtado A, Chiconato DA, Prado RM, et al. Silicon application induces changes C:N:P stoichiometry and enhances stoichiometric homeostasis of sorghum and sunflower plants under salt stress. Saudi J Biol Sci. 2020;27:3711–9. https://doi.org/10.1016/j.sjbs.2020.08.017 .

Article   CAS   PubMed   PubMed Central   Google Scholar  

Carmello QAC, Rossi F. Hidroponia: solução nutritiva – Manual. Viçosa: Centro de Produções Técnicas; 1997.

Carvalho JM, Barreto RF, Prado RM, et al. Elevated CO 2 and warming change the nutrient status and use efficiency of Panicum maximum Jacq. PlosOne. 2020a;15:e0223937. https://doi.org/10.1371/journal.pone.0223937 .

Carvalho JM, Barreto RF, Prado RM, et al. Elevated [CO 2 ] and warming increase the macronutrient use efficiency and biomass of Stylosanthes capitata Vogel under field conditions. J Agron Crop Sci. 2020b;206:597–606.

Castellane PD, Araujo JAC. Cultivo sem solo - Hidroponia. Funep: Jaboticabal; 1995.

Cavalcante VS, Prado RM, Vasconcelos RL, et al. Growth and nutritional efficiency of watermelon plants grown under macronutrient deficiencies. HortScience. 2019;54:738–42. https://doi.org/10.21273/HORTSCI13807-18 .

Cobra Netto A, Acoorsi WR, Malavolta E. Studies on the mineral nutrition of the bean plant ( Phaseolus vulgaris L., var). An Esc Super Agric Luiz de Queiroz. 1971;28(257):274. https://doi.org/10.1590/S0071-12761971000100018 .

Coelho AM, França GE, Pitta GVE, et al. Cultivo do milho: diagnose foliar do estado nutricional da planta. Sete Lagoas: Embrapa; 2002.

Cometti NN, Furlani PR, Ruiz HA, et al. Soluções nutritivas: formulação e aplicações. In: Fernandes MS, editor. Nutrição mineral de plantas. Viçosa: Sociedade Brasileira de Ciência do Solo; 2006. p. 89–114.

Dantas JP, Bergamin Filho H, Malavolta E. Studies on the mineral nutrition of Vigna Sinensis. II. Effects of deficiencies of macronutrients on growth, yield and leaf composition. An Esc Super Agric Luiz de Queiroz. 1979;36:247–57. https://doi.org/10.1590/S0071-12761979000100014 .

David CHO, Paiva Neto VB, Campos CNS, et al. Nutritional disorders of macronutrients in Bletia catenulata . HortScience. 2019;54:1836–9. https://doi.org/10.21273/HORTSCI14284-19 .

Deus ACF, Prado RM, ALVAREZ RCF, et al. Role of silicon and salicylic acid in the mitigation of nitrogen deficiency stress in rice plants. SILICON. 2019;11:1–9. https://doi.org/10.1007/s12633-019-00195-5 .

Dias LE, Faria SM, Franco AA. Crescimento de mudas de Acacia mangium Willd em resposta à omissão de macronutrientes. Rev Árvore. 1994;18:123–31.

Djanaguiraman M, Durga Devi D, Shankler AK, et al. Selenium – na antioxidative protectant in soybean during senescence. Plant Soil. 2005;272:77–86. https://doi.org/10.1007/s11104-004-4039-1 .

Epstein E. Mineral nutrition of plants: principles and perspectives. New York: Wiley; 1972.

Epstein E. Nutrição mineral das plantas e perspectivas. Portuguese edition: Malavolta E. São Paulo: Universidade de São Paulo; 1975. p. 1975.

Epstein E. Photosynthesis, inorganic plant nutrition, solutions, and problems. Photosynth Res. 1995;46:37–9. https://doi.org/10.1007/BF00020413 .

Epstein E. Silicon in plant nutrition. In: abstracts of the 2rd silicon in agriculture conference. Tsuruoka: Japanese Society of Soil Science and Plant Nutrition; 2002. p. 1.

Epstein E, Bloom A. Nutrição mineral de plantas: princípios e perspectivas. In: Maria Edna Tenório Nunes, Português editors. Londrina: Planta; 2006.

Erying C, Ling Q, Yanbing Y, et al. Variability of nitrogen use efficiency by foxtail millet cultivars at the seedling stage. Pesq Agropec Bras. 2020;55:1–9. https://doi.org/10.1590/s1678-3921.pab2020.v55.00832 .

Fageria NK. Potassium use efficiency of upland rice genotypes. Pesq Agropec Bras. 2000;35:2115–20. https://doi.org/10.1590/S0100-204X2000001000025 .

Fageria NK, Baligar VC, Jones CA. Rice in. In: Fageria NK, Baligar VC, Jones CA, editors. Growth and mineral nutrition of field crops. M. New York: Dekker; 1997. p. 283–343.

Fasabi JAV, Carências de macro e micronutrientes em plantas de malva (Urena lobata), variedade BR-01. Dissertação, Faculdade de Ciências Agrárias do Pará. 1996.

Felisberto G, Prado RM, Oliveira RLL, et al. Are nanosilica, potassium silicate and new soluble sources of silicon effective for silicon foliar application to soybean and rice plants? SILICON. 2020;12:00668. https://doi.org/10.1007/s12633-020-00668-y .

Fernandes LA, Alves DS, Ramos SJ, et al. Mineral nutrition of Cyclanthera pedata . Pesq Agropec Bras. 2005;40:719–22. https://doi.org/10.1590/S0100-204X2005000700014 .

Ferreira RLC, Prado RM, Souza Júnior JP, et al. Oxidative stress, nutritional disorders, and gas exchange in lettuce plants subjected to two selenium sources. J Soil Sci Plant Nutr. 2020;20 https://doi.org/10.1007/s42729-020-00206-0 .

Flores RA, Borges BMMN, Almeida HJ, et al. Growth and nutritional disorders of eggplant cultivated in nutrients solutions with suppressed macronutrients. J Plant Nutr. 2014;38:1097–9. https://doi.org/10.1080/01904167.2014.963119 .

Flores RA, Arruda EM, Damin V, et al. Physiological quality and dry mass production of Sorghum bicolor following silicon (Si) foliar application. Aust J Crop Sci. 2018;12:631–8. https://doi.org/10.21475/ajcs.18.12.04.pne967 .

Föhse D, Claassen N, Jungk A. Phosphorus efficiency of plants. I. External and internal P requirement and P uptake efficiency of different plant species. Plant Soil. 1988;110:101–9. https://doi.org/10.1007/BF00010407 .

Franco CF, Prado RM. Nutrition solutions in the culture of guava: effect in the development and nutricional state. Acta Scient Agron. 2006;28:199–205 https://doi.org/10.4025/actasciagron.v28i2.1042 .

Frazão JJ, Prado RM, de Souza Júnior JP, et al. Silicon changes C:N:P stoichiometry of sugarcane and its consequences for photosynthesis, biomass partitioning and plant growth. Sci Rep. 2020;10:12492. https://doi.org/10.1038/s41598-020-69310-6 .

Freitas FA, Koop MM, Souza RO, et al. Nutrient absorption in aluminum stressed rice plants under hydroponic culture. Ciênc Rural. 2006;36:72–9. https://doi.org/10.1590/S0103-84782006000100011 .

Furlani PR, Clark RB. Screening sorghum for aluminium tolerance in nutrient solutions. Agron J. 1981;73:587–94.

Furlani PR. Cultivo de alface pela técnica de hidroponia – NFT. Campinas: Instituto Agronômico; 1995. 18p.

Gabelman WH, Gerloff GC. The search for and interpretation of genetic controls that enhance plant growth under deficiency levels of a macronutrient. Plant Soil. 1983;72:335–50.

Gonçalves FC, Neves OSC, Carvalho JG. Nutritional deficiency in “Umbuzeiro” seedlings caused by the omission of macronutrients. Pesq Agropec Bras. 2006;41:1053–7. https://doi.org/10.1590/S0100-204X2006000600023 .

Goussain MM, Moraes JC, Carvalho JG, et al. Effect of silicon application on corn plants upon the biological development of the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Neotrop Entomol. 2002;31:305–10. https://doi.org/10.1590/S1519-566X2002000200019 .

Graham RD. Breeding for nutritional characteristics in cereals. In: Tinker PB, Lauchli A, editors. Advances in plant nutrition. New York: Praeger; 1984. p. 57–102.

Grant CA, Flaten DN, Tomasiewics DJ, et al. A importância do fósforo no desenvolvimento inicial da planta. Informações Agronômicas. 2001;95:1–5.

Guedes VHF, Prado RM, Frazão RJJ, et al. Foliar-applied silicon in sorghum ( Sorghum bicolor L.) alleviate zinc deficiency. SILICON. 2020;13:0825–3. https://doi.org/10.1007/s12633-020-00825-3 .

Haag HP, Sarruge JR, Camargo PN, et al. Studies on the mineral diet of coffee. XXVI. Effects of multiple deficiencies in mineral appearance, growth and composition. An Esc Super Agric Luiz de Queiroz. 1969;26:119–39. https://doi.org/10.1590/S0071-12761969000100011 .

Habermann E, Oliveira EAD, Contin DR, et al. Warming and water deficit impact leaf photosynthesis and decrease forage quality and digestibility of a C4 tropical grass. Physiol Plantarum. 2019;165:383–402. https://doi.org/10.1111/ppl.12891 .

Hoagland DR, Arnon DI. The water culture method for growing plants without soils. Berkeley: California Agricultural Experimental Station; 1950. 347p

Jensen MH, Collins WL. Hydroponic vegetable production. In: Janick J, editor. Horticultural reviews. New York: Willey Press; 1985. p. 483–557.

Jo J, Jang YS, Kim KY, et al. Isolation of ALU1-P gene encoding a protein with aluminum tolerance activity from arthrobacter viscosus. Biochem Bioph Res Co. 1997;239:835–9. https://doi.org/10.1006/bbrc.1997.7567 .

Jones JB Jr. Plant nutrition manual. Boca Raton: CRC Press; 1998. 147p

Kathpalia R, Bhatla SC. Plant mineral nutrition. In: Bhatla SC, Lal MA, editors. Plant physiology, development and metabolism. Singapore: Springer; 2018. p. 37–81. https://doi.org/10.1007/978-981-13-2023-1_2 .

Chapter   Google Scholar  

Kolesnikov M, Gins V. Forms of silicon in medicinal plants. Appl Biochem Microbiol. 2001;37:524–7.

Körndorfer GH, Snyder GH, Ulloa M, et al. Calibration of soil and plant silicon analysis for rice production. J Plant Nutr. 2001;24:1071–84. https://doi.org/10.1081/PLN-100103804 .

Körndorfer GH, Pereira HS, Camargo MS. Papel do silício na produção da cana-de-açúcar. Stab. 2002;21:6–9.

Lata-Tenesaca LF, Prado RM, Piccolo CM et al. Silicon modifies C:N:P stoichiometry, and increases nutrient use efficiency and productivity of quinoa. Sci Rep 2021;11:9893. https://doi.org/10.1038/s41598-021-89416-9 .

Lauchli A. Soil science in the next twenty five years: does a biotechnology play a role? Soil Sci Soc Am J. 1987;51:1405–9. https://doi.org/10.2136/sssaj1987.03615995005100060003x .

Lavres Junior J, Boaretto RM, Silva MLS, et al. Deficiencies of macronutrients on nutritional status of castor bean cultivar Iris. Pesq Agropec Bras. 2005;40:145–51. https://doi.org/10.1590/S0100-204X2005000200007 .

Lehr JJ. Sodium as a plant nutrition. J Sci Food Agric. 1953;4:460–1. https://doi.org/10.1002/jsfa.2740041002 .

Li B, Mckeand SE, Allen HL. Genetic variation in nitrogen use efficiency of loblolly pine seedlings. For Sci. 1991;37:613–26.

Lima Filho OF, Malavolta E. Symptoms of nutritional disorders in stevia ( Stevia rebaudiana (bert.) bertoni). Sci Agric. 1997;54:53–61. https://doi.org/10.1590/S0103-90161997000100008 .

Loué A. Oligoelements en agriculture. Paris: SCPA Nathan; 1993. 577p

Ma JF, Takahashi E. Soil, fertiliser, and plant silicon research in Japan. Amsterdam: Elsevier; 2002.

Ma JF, Yamaji N. A cooperative system of silicon transport in plants. Trends Plant Sci. 2015;20:435–42. https://doi.org/10.1016/j.tplants.2015.04.007 .

Malavolta E. Elementos de nutrição de plantas. São Paulo: Agronômica Ceres; 1980. 251p

Malavolta E. Manual de nutrição mineral de plantas. São Paulo: Agronômica Ceres; 2006.

Malavolta E, Vitti GC, Oliveira SA. Avaliação do estado nutricional das plantas: princípios e aplicações. Piracicaba: Associação Brasileira de Potassa e do Fósforo; 1997. 319p

Mantovani C, Prado RM, Pivetta KFL. Silicon foliar application on nutrition and growth of Phalaenopsis and Dendrobium orchids. Sci Hortic. 2018;18:83–92. https://doi.org/10.1016/j.scienta.2018.06.088 .

Mantovani C, Pivetta KFL, Prado RM, et al. Silicon toxicity induced by different concentrations and sources added to in vitro culture of epiphytic orchids. Sci Hortic. 2020;265:109272. https://doi.org/10.1016/j.scienta.2020.109272 .

Marin A, Santos DMM, Banzatto DA, et al. Seed germination of pigonpea ( Cajanus cajan (L.) Millsp.) under water stress and aluminum sublethal doses. Bragantia. 2004;63:13–24. https://doi.org/10.1590/S0006-87052004000100002 .

Marschner H. Mineral nutrition of higher plants. London: Academic Press; 1986.

Marschner H. Mineral nutrition of higher plants. London: Academic; 1995.

Martinez HEP, Silva Filho JB. Introdução ao cultivo hidropônico. Viçosa: Universidade Federal; 2004.

Mccray JM, Ezenwa IV, Rice RW et al. Sugarcane plant nutrient diagnosis. 2006. http://edis.ifas.ufl.edu/sc075 . Accessed 21 Sept 2006

Mendonça RJ, Cambraia J, Oliva MA, et al. Rice cultivars ability to change nutrient solution pH in the presence of aluminum. Pesq Agropec Bras. 2005;40:447–52. https://doi.org/10.1590/S0100-204X2005000500004 .

Mengel K, Kirkby EA. Principles of plant nutrition. Worblaufen-Bern: International Potash Institute; 1987.

Menosso OG, Costa JA, Anghinoni I, et al. Root growth and production of organic acids by soybean cultivars with different tolerance to aluminum. Pesq Agropec Bras. 2001;36:1339–45. https://doi.org/10.1590/S0100-204X2001001100003 .

Miyake Y, Takahashi E. Silicon deficiency of tomato plant. Soil Sci Plant Nutr. 1978;24:175–89. https://doi.org/10.1080/00380768.1978.10433094 .

Miyake Y, Takahashi E. Effect of silicon on the growth of soybean plants in solution culture. Soil Sci Plant Nutr. 1985;31:625–36. https://doi.org/10.1080/00380768.1985.10557470 .

Monteiro FA, Ramos AKB, Carvalho DD, et al. Growth of Brachiaria brizantha Stapf. cv. Marandu in nutrient solution with macronutrient omissions. Sci Agric. 1995;52:135–41. https://doi.org/10.1590/S0103-90161995000100022 .

Morgan PW (1990) Effects of abiotic stresses on plant hormone systems. In: Alscher RC, Cumming JR Stress responses in plants: adaptation and acclimation mechanisms. Willey-Liss, New York, pp. 113–146.

Müntz K. Deposition of storange proteins. Plant Mol Biol. 1998;38:77–99.

Article   PubMed   Google Scholar  

Oliveira KR, Souza JP Jr, Bennett SJ. Exogenous silicon and salicylic acid applications improve tolerance to boron toxicity in field pea cultivars by intensifying antioxidant defence systems. Ecot Environ Safety. 2020a;201:110778. https://doi.org/10.1016/j.ecoenv.2020.110778 .

Oliveira RLL, Prado RM, Felisberto G, et al. Silicon mitigates manganese deficiency stress by regulating the physiology and activity of antioxidant enzymes in sorghum plants. J Soil Sci Plant Nutr. 2019;19:524–534. https://doi.org/10.1007/s42729-019-00051-w .

Oliveira KS, Prado RM, Guedes VHF. Leaf spraying of manganese with silicon addition is agronomically viable for corn and sorghum plants. J Soil Sci Plant Nutr. 2020b;20:00173–6. https://doi.org/10.1007/s42729-020-00173-6 .

Osório CRWS, Teixeira GCM, Barreto RF, et al. Macronutrient deficiency in snap bean considering physiological, nutritional, and growth aspects. PlosOne. 2020;15:e0234512. https://doi.org/10.1371/journal.pone.0234512 .

Peixoto MM, Flores RA, Couto CA, et al. Silicon application increases biomass yield in sunflower by improving the photosynthesizing leaf area. SILICON. 2020;13:0818–2. https://doi.org/10.1007/s12633-020-00818-2 .

Perry C, Tucker K. Biosilicification: the role of the organic matrix in the structure control. J Biol Inorg Chem. 2000;5:537–50.

Prado RM. Effect of limestone application on development, nutritional status and fruit production of guava and star fruit during three years in orchards under implantation. Jaboticabal, São Paulo State University - Doctoral thesis, 2003.

Prado RM, Leal RM. Nutritional disorders due to deficiency in sunflower var. Catissol 01. Pesq Agropec Trop. 2006;36:173–9.

Prado RM, Natale W. Effect of application of calcium silicate on growth, nutritional status and dry matter production of passion fruit seedlings. Rev Bras Eng Agríc Ambient. 2005;9:185–190. https://doi.org/10.1590/S1415-43662005000200006 .

Prado RM, Correa MCM, Cintra ACO et al. Micronutrients released from one basic slag applied a ultisol cultivated with guava plants ( Psidium guajava L.). Rev Bras Frutic. 2002a;24:536–542. https://doi.org/10.1590/S0100-29452002000200051 .

Prado RM, Coutinho ELM, Roque CG et al. Evaluation of slag and calcareous rocks as corrective of the acidity of the ground in the culture of lettuce Pesq Agrop Bras. 2002b;37:539–546. https://doi.org/10.1590/S0100-204X2002000400016 .

Prado RM, Cruz FJR, Ferreira RLC. Selenium biofortification and the problem of its safety. In: Shiomi N, editor. Superfood and functional food: an overview of their processing and utilization. Rijeka: InTech; 2017. p. 221–38.

Prado RM, Felisberto G, Barreto RF. Nova abordagem do silício na mitigação de estresse por deficiência de nutrientes. In: Prado RM, Campos CNS, editors. Nutrição e adubação de grandes culturas. Jaboticabal: FCAV; 2018. p. 17–26.

Raboy V. Seeds for a better future: ‘low phytate’ grains help to overcome malnutrition and reduce pollution. Trends Plant Sci. 2001;6:458–62. https://doi.org/10.1016/S1360-1385(01)02104-5 .

Rains DW. Mineral metabolism. In: Bonner J, Varner JE, editors. Plant biochemistry. New York: Academic; 1976. p. 561–98.

Rocha Filho JVC, Haag HP, Oliveira GD. The effects of mineral nutrient deficiencies on Eucalyptus urophylla growth in nutrient solutions. An Esc Super Agric Luiz de Queiroz. 1978;35:19–34. https://doi.org/10.1590/S0071-12761978000100002 .

Rocha JR, Prado RM, Teixeira GCM et al. Si fertigation attenuates water stress in forages by modifying carbon stoichiometry, favouring physiological aspects. J Agron Crop Sci. 2021;207:12479. https://doi.org/10.1111/jac.12479 .

Rosolem CA, Leite VM. Coffee leaf and stem anatomy under boron deficiency. Rev Bras Ciênc Solo. 2007;31:477–83. https://doi.org/10.1590/S0100-06832007000300007 .

Rozane DE, Natale W, Prado RM, et al. Size of samples for nutritional status assessment of mango trees. Rev Bras Frutic. 2007;29:371–6. https://doi.org/10.1590/S0100-29452007000200035 .

Rublo G, Liao H, Yan X, et al. Topsoil foraging and its role in plant competitiveness for phosphorus in common bean. Crop Sci. 2003;43:598–607. https://doi.org/10.2135/cropsci2003.5980 .

Salvador JO, Muraoka T, Rossetto R, et al. Symptoms of mineral deficiencies in cupuaçu plants ( Theobroma gramdiflorum ) grown in nutrient solution. Sci Agric. 1994;51:407–14. https://doi.org/10.1590/S0103-90161994000300005 .

Salvador JO, Moreira A, Muraoka T. Visual symptoms of micronutrient deficiency and of mineral content in guava young plant leaves. Pesq Agropec Bras. 1999;34:1655–62. https://doi.org/10.1590/S0100-204X1999000900016 .

Samonte SOPB, Wilson LT, Medley JC, et al. Nitrogen utilization efficiency: relationships with grain yield, grain protein, and yield-related traits in rice. Agron J. 2006;98:168–76. https://doi.org/10.2134/agronj2005.0180 .

Santi A, Camargos SL, Scaramuzza WLMP, et al. The macronutrients deficiency in sorghum. Ciênc Agrotec. 2006;30:228–33. https://doi.org/10.1590/S1413-70542006000200006 .

Santos OS. Hidroponia da alface. Santa Maria: Imprensa Universitária; 2000.

Santos LCN, Teixeira GCM, Prado RM, et al. Response of pre-sprouted sugarcane seedlings to foliar spraying of potassium silicate, sodium and potassium silicate, nanosilica and monosilicic acid. Sugar Tech. 2020;22:00833. https://doi.org/10.1007/s12355-020-00833-y .

Sarcinelli TS, Ribeiro ES Jr, Dias LE, et al. Symptoms of nutritional deficiency in seedlings of Acacia holosericea submitted to absence of macronutrients. Rev Árvore. 2004;28:173–81. https://doi.org/10.1590/S0100-67622004000200003 .

Siddiqi MY, Glass ADM. Utilisation index: a modified approach to the estimation and comparison of nutrient utilisation efficiency in plants. J Plant Nutr. 1981;4:289–302. https://doi.org/10.1080/01904168109362919 .

Silva JRS, Falcão NPS. Characterization of symptoms of nutritional deficiencies in peach palm cultivated in nutrient solution. Acta Amazon. 2002;32:529–39. https://doi.org/10.1590/1809-43922002324539 .

Silva Junior GB, Prado RM, Campos CNS, et al. Silicon mitigates ammonium toxicity in yellow passion fruit seedlings. Chil J Agric Res. 2019;79:425–34. https://doi.org/10.4067/S0718-58392019000300425 .

Silva ES, Prado RM, Soares AAVL, et al. Response of corn seedlings ( Zea mays L) to different concentrations of nitrogen in absence and presence of silicon. SILICON. 2020;12:00480–8. https://doi.org/10.1007/s12633-020-00480-8 .

Silva JLF, Prado RM. Elucidating the action mechanisms of silicon in the mitigation of phosphorus deficiency and enhancement of its response in sorghum plants. J Plant Nutr. 2021;45:8155. https://doi.org/10.1080/01904167.2021.1918155 .

Silva DL, Prado RM, Tenesaca LFL et al. Silicon attenuates calcium deficiency by increasing ascorbic acid content, growth and quality of cabbage leaves. Sci Rep. 2021;11:1770. https://doi.org/10.1038/s41598-020-80934-6 .

Souza Júnior JP, Prado RM, Sarah MMS, et al. Silicon mitigates boron deficiency and toxicity in cotton cultivated in nutrient solution. J Plant Nutr Soil Sci. 2019;182:805–14. https://doi.org/10.1002/jpln.201800398 .

Souza Junior JP, Frazão JJ, Morais TCB, et al. Foliar spraying of silicon associated with salicylic acid increases silicon absorption and peanut growth. SILICON. 2020;12:00517. https://doi.org/10.1007/s12633-020-00517-y .

Souza JZ, Prado RM, Silva SLO, et al. Silicon leaf fertilization promotes biofortification and increases dry matter, ascorbate content, and decreases post-harvest leaf water loss of chard and kale. Comm Soil Sci Plant Anal. 2018;50:164–72. https://doi.org/10.1080/00103624.2018.1556288 .

Stein AJ. Global impacts of human mineral malnutrition. Plant Soil. 2010;335:133–54. https://doi.org/10.1007/s11104-009-0228-2 .

Subbarao GV, Ito O, Berry WL, et al. Sodium – a functional plant nutrient. Crit Rev Plant Sci. 2003;22:391–416. https://doi.org/10.1080/07352680390243495 .

Svecnjak Z, Rengel Z. Canola cultivars differ in nitrogen utilization efficiency at vegetative stage. Field Crops Res. 2006;97:221–6. https://doi.org/10.1016/j.fcr.2005.10.001 .

Swiader JM, Chyan Y, Freiji FG. Genotypic differences in nitrate uptake and utilization efficiency in pumpkin hybrids. J Plant Nutr. 1994;17:1687–99. https://doi.org/10.1080/01904169409364840 .

Teixeira GCM, Prado RM, Rocha AMS, et al. Silicon in pre-sprouted sugarcane seedlings mitigates the effects of water deficit after transplanting. J Soil Sci Plant Nutr. 2020a;20:00170–4. https://doi.org/10.1007/s42729-019-00170-4 .

Teixeira GCM, Prado RM, Oliveira KS, et al. Silicon increases leaf chlorophyll content and iron nutritional efficiency and reduces iron deficiency in sorghum plants. J Soil Sci Plant Nutr. 2020b;20:1311–20. https://doi.org/10.1007/s42729-020-00214-0 .

Veloso CAC, Muraoka T. Diagnosis of macronutrient deficiency symptoms in black pepper ( Piper nigrum L.). Sci Agric. 1993;50:232–6. https://doi.org/10.1590/S0103-90161993000200010 .

Veloso CAC, Muraoka T, Malavolta E, et al. Diagnosis of macronutrient deficiencies in black pepper. Pesq Agropec Bras. 1998;33:1883–8.

Viciedo DO, Prado RM, Martinez CAH, et al. Short-term warming and water stress affect Panicum maximum Jacq. stoichiometric homeostasis and biomass production. Sci Total Environ. 2019a;681:267–74. https://doi.org/10.1016/j.scitotenv.2019.05.108 .

Viciedo DO, Prado RM, Toledo RL, et al. Silicon supplementation alleviates ammonium toxicity in sugar beet ( Beta vulgaris L.). J Soil Sci Plant Nutr. 2019b;19:413–9. https://doi.org/10.1007/s42729-019-00043-w .

Viciedo DO, Prado RM, Toledo RL, et al. Physiological role of silicon in radish seedlings under ammonium toxicity. Food Sci Tech. 2020a;100:10587. https://doi.org/10.1002/jsfa.10587 .

Viciedo DO, Prado RM, Martinez CAH, et al. Water stress and warming impact nutrient use efficiency of Mombasa grass ( Megathyrsus maximus ) in tropical conditions. J Agron Crop Sci. 2020b;206:12452. https://doi.org/10.1111/jac.12452 .

Viciedo DO, Prado RM, Martinez CAH, et al. Changes in soil water availability and air-temperature impact biomass allocation and C:N:P stoichiometry in different organs of Stylosanthes capitata Vogel. J Environ Manag. 2021;278:111540. https://doi.org/10.1016/j.jenvman.2020.111540 .

Viégas IJM, Carvalho JG, Rocha Neto OG, et al. Carência de macronutrientes em plantas de quina. Belém: Embrapa; 1998.

Viegas IJM, Frazão DAC, Thomaz MAA, et al. Nutritional limitations for Euterpe oleracea in yellow Latosol of Para state - Brazil. Rev Bras Frutic. 2004a;26:382–4. https://doi.org/10.1590/S0100-29452004000200052 .

Viegas IJM, Thomaz MAA, Silva JF, et al. Effect of omission of macronutrient and boron on growth, on symptoms of nutritional deficiency and mineral composition in camucamuzeiro plants ( Myrciaria dubia ). Rev Bras Frutic. 2004b;26:315–9. https://doi.org/10.1590/S0100-29452004000200032 .

Vitorello VA, Capaldi FR, Stefanuto VA. Recent advances in aluminum toxicity and resistance in higher plants. Braz J Plant Physiol. 2005;17:129–43. https://doi.org/10.1590/S1677-04202005000100011 .

Warington K. The effect of boric acid and borax on the broad bean and certain other plants. Ann Bot. 1923;37:629–72. https://doi.org/10.1093/oxfordjournals.aob.a089871 .

Wen TN, Li C, Chien CS. Ubiquity of selenium containing t RNA in plants. Plant Sci. 1988;57:185–93. https://doi.org/10.1016/0168-9452(88)90124-0 .

Yamamoto Y, Kobayashi Y, Devi SR et al. Aluminum toxicity is associated with mitochondrial dysfunction and the production of reactive oxygen species in plant cells. Plant Physiol. 2002;128:63–72. https://doi.org/10.1104/pp.010417 .

Zakir Hossain AKM, Koyama H, Hara T. Growth and cell wall properties of two wheat cultivars differing in their sensitivity to aluminum stress. J Plant Physiol. 2006;163:39–47. https://doi.org/10.1016/j.jplph.2005.02.008 .

Download references

Author information

Authors and affiliations.

São Paulo State University, Jaboticabal, São Paulo, Brazil

Renato de Mello Prado

You can also search for this author in PubMed   Google Scholar

Rights and permissions

Reprints and permissions

Copyright information

© 2021 Springer Nature Switzerland AG

About this chapter

de Mello Prado, R. (2021). Introduction to Plant Nutrition. In: Mineral nutrition of tropical plants. Springer, Cham. https://doi.org/10.1007/978-3-030-71262-4_1

Download citation

DOI : https://doi.org/10.1007/978-3-030-71262-4_1

Published : 13 July 2021

Publisher Name : Springer, Cham

Print ISBN : 978-3-030-71261-7

Online ISBN : 978-3-030-71262-4

eBook Packages : Biomedical and Life Sciences Biomedical and Life Sciences (R0)

Share this chapter

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Publish with us

Policies and ethics

• Find a journal
• Track your research

• Search Menu
• Sign in through your institution
• Advance articles
• Darwin Reviews
• Special Issues
• Expert View
• Flowering Newsletter Reviews
• Technical Innovations
• Editor's Choice
• Virtual Issues
• Community Resources
• Reasons to submit
• Author Guidelines
• Peer Reviewers
• Submission Site
• Open Access
• About Journal of Experimental Botany
• About the Society for Experimental Biology
• Editorial Board
• Advertising and Corporate Services
• Journals Career Network
• Permissions
• Self-Archiving Policy
• Dispatch Dates
• Journal metrics
• Journals on Oxford Academic
• Books on Oxford Academic

Article Contents

Transport of nitrate and ammonium, nitrogen sensing and signalling: exciting times, from model plants to crops: rising concern, future perspectives, acknowledgements, nitrogen nutrition in plants: rapid progress and new challenges.

• Article contents
• Figures & tables
• Supplementary Data

Alain Gojon, Nitrogen nutrition in plants: rapid progress and new challenges, Journal of Experimental Botany , Volume 68, Issue 10, 1 May 2017, Pages 2457–2462, https://doi.org/10.1093/jxb/erx171

• Permissions Icon Permissions

As a main feature of plant autotrophy, assimilation of inorganic nitrogen is not only of fundamental scientific interest, but also a crucial factor in crop productivity. In its broad sense – from root uptake of various forms of N in the soil to allocation of N assimilates to different organs – it involves a wide range of physiological processes whose mechanisms are far from being fully understood. The aim of this special issue is to provide a wide overview of recent progress in this field, and to draw an interdisciplinary picture of the prospects for future research.

Increasing demand for food, the requirement for a more environmentally friendly agriculture and future risks arising from climate change are all associated with the urgent need to improve N use efficiency in plants ( Zhang et al. , 2015 ). For more than 50 years, N fertilizers have been an efficient way to enhance crop production. Further increases are an absolute requirement in meeting the needs of a rapidly growing population, but agriculture must now find alternative solutions to ensure adequate N nutrition of plants. Indeed, the amount of N fertilizers used worldwide is now so huge that it almost equals the natural global N fixation from the atmosphere into the bio-lithosphere. The consequence of such an enormous anthropogenic input is that the bio-geochemical N cycle is running out of control ( Steffen et al. , 2015 ), resulting in major detrimental effects on the environment such as nitrate pollution of freshwater and coastal ecosystems ( Galloway, 2003 ). Moreover, climate change brings an additional, unexpected threat as many studies highlight that the continuous elevation of atmospheric CO 2 concentration will negatively impact the N status of most C 3 plants, leading to lowered nutritional value of crops ( Myers et al. , 2014 ).

Is there any hope of meeting this challenge successfully? The answer is certainly yes. In fact, it is now clear that the continuous decrease of N use efficiency in agriculture can be stopped and even reversed. Furthermore, increasing both yield and N use efficiency is possible and has already been achieved in several countries ( Zhang et al. , 2015 ; Hawkesford, 2017 ). The problem is obviously multi-factorial, but plant scientists do have a pivotal role as the performance of individual crop genotypes is at the heart of the improvement of N use efficiency in agriculture. Innovative solutions aimed at ecological intensification will have to be proposed – for example, these might be based on beneficial interactions between plants and soil microorganisms, including N 2 -fixing symbioses. However, it is easy to predict that reducing the use of synthetic N fertilizers in agriculture will not be realistic for quite a while, and that a more efficient use of mineral N taken up from the soil will remain a major goal for plant breeding.

The ‘Nitrogen Nutrition of Plants’ symposia are milestones allowing the associated, interdisciplinary scientific community to exchange ideas on recent findings concerning the mechanisms of inorganic N assimilation by plants ( Box 1 ). From the beginning, Journal of Experimental Botany has been at the leading edge in publishing research from this field ( Box 2 ). The reviews in this special issue collectively represent a major update on this topic, covering a wide range of genetic, molecular, physiological and developmental aspects of N nutrition in various plant species. Furthermore, recent advances that will enable this fundamental research in model plants to improve N use efficiency in crops are considered.

The EMBO Conference Nitrogen2016 (Montpellier, France) continued a long-standing tradition of international conferences on nitrogen nutrition in plants, initiated in Europe by ENAAG (European Nitrate and Ammonium Assimilation Group, focusing on physiology and eco-physiology, 1986) and NAMGA (Nitrate Assimilation: Molecular and Genetic Aspects, 1982). Despite a common focus on the assimilation of inorganic nitrogen, these two groups initially functioned separately due to the different disciplines they represented, but as the borders separating them receded to give rise to new approaches (e.g. molecular physiology, functional genomics), the two organizations first held a joint meeting (Nitrogen2007, Lancaster, UK) and then merged. As a consequence, Nitrogen2007 was the founder meeting of a new series of conferences addressing a larger international audience, with the First (Nitrogen2010) and Second (Nitrogen2013) International Symposia on the Nitrogen Nutrition of Plants in Inuyama City (Japan, 2010) and Puerto Varas (Chile, 2013).

Although the initial focus on the assimilation of inorganic nitrogen is still strong, the Nitrogen Symposia now cover a wide range of approaches, allowing cross-fertilization of disciplines and fostering rapid progress in our understanding. Focusing on rice, the image summarizes current thinking on the contribution of NO 3 − transporters for improving crop nitrogen use and efficiency (NUE) and yield (reproduced, with permission, from Fan et al. , 2017 : yellow box, positive effects on rice NO 3 − uptake, transport and remobilization in normal growth conditions; grey box, positive effects on NUE and yield under salinity; see Fan et al. , 2017 , for further details).

Journal of Experimental Botany ( JXB ) has accompanied the Nitrogen Symposia from the very beginning, with dedicated special issues: ‘Nitrogen nutrition’ ( Forde et al. , 2007 ); ‘Nitrogen: molecular biology, ecophysiology and beyond’ ( Sakakibara et al. , 2011 ); and ‘Plant nitrogen nutrition’ in 2014 (see also reviews on nitrogen utilization in 2012: Saez et al. , 2012 ). Nitrogen nutrition is also prominent in related special issues, such as ‘Nutrient sensing and signalling’ ( Takahashi, 2014 ) and ‘Plant membrane biology’ ( Gilliham, 2011 ). Therefore, JXB is a landmark journal for those interested in a comprehensive and timely overview of current knowledge in the field. The image is taken from Hirel et al. (2007) , one of the most highly cited JXB papers on nitrogen nutrition, appearing in the special issue associated with Nitrogen2007, the founder meeting of the current series of Nitrogen conferences. The maize ear phenotypes in GS1-deficient mutants and overexpressing lines are from N conditions which are suboptimal (N + ) or limiting (N – ): (A) wild type (WT), gln1.4 , gln1.3 , gln1.3 / gln1.4 mutants; (B) WT null segregants and T4 transgenic lines 1 and 9 overexpressing Gln1-3 cDNA (reproduced, with permission, from Hirel et al. , 2007 ).

Among the many different steps involved in inorganic N utilization by plants, those associated with the transport of nitrate and ammonium have received increasing attention over the past two decades. It is now clear that many (if not most) of the membrane transporter proteins involved have been identified at the molecular level in model species, and there is a general conservation of the related gene families between species, allowing fast progress in research on crops.

For nitrate, four gene families – NPF ( NRT1 ), NRT2 , CLC and SLAC1/SLAH – include all transporters and channels so far identified ( Fan et al. , 2017 ; Li et al. , 2017 ). In Arabidopsis, these collectively represent more than 60 genes. Despite this complexity, nearly all steps of nitrate transport have been associated with the function of at least one member of these families: uptake by root cells, long-distance translocation between organs, and intracellular transport between cytoplasm and vacuole ( Fan et al. , 2017 ). Molecular understanding of ammonium transport is focused on the AMT1 family of high-affinity transporters ( Li et al. , 2017 ), which have a predominant role in root uptake. Further work is still needed to reach a full understanding of the mechanisms of nitrate and ammonium transport, but progress has already been impressive. For instance, all transporters contributing significantly to the high-affinity root uptake of these ions from the external medium have been identified in Arabidopsis, namely NRT2.1, NRT2.2, NRT2.4 and NRT2.5 for nitrate, and AMT1.1, AMT1.2, AMT1.3 and AMT1.5 for ammonium. This is evidenced by the phenotypes of multiple mutants in the corresponding genes, which are almost totally impaired in root N acquisition of either N source ( Yuan et al. , 2007 ; Lezhneva et al. , 2014 ). Although this work of functional characterization is largely still to be completed in other species, the overall structure of the nitrate and ammonium transport systems seems to be rather well conserved across the plant kingdom ( Fan et al. , 2017 ), and detailed genomic information is now available in many species, such as rice ( Li et al. , 2017 ) and trees ( Castro-Rodríguez et al. , 2017 ). However, marked specificities exist between different species, suggesting functional complexity that cannot be totally understood by just investigating model species like Arabidopsis. For instance, whereas the Arabidopsis AMT2 sub-family of high-affinity ammonium transporters is only represented by a single member of unclear function (AMT2.1), there are nine AMT2 genes in the Populus trichocarpa genome ( Castro-Rodriguez et al. , 2017 ).

When compared with this very active investigation of nitrate and ammonium transporters, elucidation of the molecular mechanisms of amino acid transport still appears to be at an early stage ( Tegeder, 2012 ). However, transport of amino acids is essential for N partitioning between organs ( Tegeder, 2014 ). Havé et al. (2017) confirm this in the context of N remobilization during senescence, a crucial process for seed N filling, stressing that little is known about the roles of many amino acid or peptide transporters up- or down-regulated during senescence.

Half of the reviews in this special issue deal with regulatory mechanisms involved in N sensing and signalling ( Bellegarde et al. , 2017 ; Calatrava et al. , 2017 ; Forde and Gent, 2017 ; Hachiya and Sakakibara, 2017 ; Jacquot et al. , 2017 ; Liu and von Wirén, 2017 ; Undurraga et al. , 2017 ). This perfectly illustrates the current strong focus on these aspects, and rapid progress being made in our understanding. It has been known for a long time that inorganic N utilization by plants is finely regulated by highly complex and sophisticated signalling pathways, activated by sensing of both external N availability and internal N status of the whole plant (see Krapp et al. , 2014 and O’Brien et al. , 2016 for additional recent reviews).

Liu and von Wirén (2017) and Undurraga et al. (2017) document the role of both ammonium and nitrate as signalling molecules triggering a wide range of molecular, physiological and developmental responses. Findings concerning the sensing mechanisms of these two ions, and the associated downstream signalling events are coming out at an unprecedented pace. Interestingly, both reviews highlight the potential role of membrane transporters in ammonium or nitrate sensing, supporting the ‘transceptor’ (transporter/receptor) concept initially reported for the MEP2 ammonium transporter in yeast ( Holsbeeks et al. , 2004 ). Indeed, increasing evidence indicates that the NPF6.3 (NRT1.1) nitrate transporter and the AMT1.1 and AMT1.3 ammonium transporters also serve as nitrate and ammonium sensors, respectively (see also Lima et al. , 2010 ; Gojon et al. , 2011 ; Bouguyon et al. , 2015 ). Although the downstream signalling pathways still remain obscure at the molecular level for ammonium, a significant number of regulatory genes or secondary signals have recently been reported for nitrate ( Undurraga et al. , 2017 ), including NLP transcription factors ( Marchive et al. , 2013 ) and calcium ( Riveras et al. , 2015 ). In addition, Calatrava et al. (2017) point out the putative signalling role of nitric oxide (NO) in regulating nitrate transport and assimilation in Chlamydomonas . As studies on this model green alga have proved to be an important source of information for understanding processes of nitrate utilization in plants, it will be of interest to determine the general significance of this signalling role. Furthermore, ammonium and nitrate signalling are not independent from each other but strongly interact, as stressed by Hachiya and Sakakibara (2017) , who review the many different effects of these interactions.

Besides perception of external availability of inorganic nitrogen through ammonium and nitrate sensing, plants also need to modulate N acquisition and utilization according to their N demand for growth. This relies on long-distance signalling of whole-plant N status, and associated local regulatory mechanisms. The mechanisms by which plants sense their N status are reviewed by Bellegarde et al. (2017) and Forde and Gent (2017) . As highlighted by both reviews, and despite many interesting candidates, both sensors and long-distance signals of internal N status are unclear at the molecular level. However, and this is an additional illustration of the very active research in this area, new developments have occurred since the publication of these papers. Indeed, a very recent report indicates that long-distance signalling of nitrate availability is ensured by a root-to-shoot-to-root relay, involving xylem-mobile peptides and phloem-mobile glutaredoxin polypeptides ( Ohkubo et al. , 2017 ). As is the case for nitrate signalling ( Undurraga et al. , 2017 ), a significant number (>12) of regulators putatively acting downstream from the signals of N status have been identified in Arabidopsis ( Bellegarde et al. , 2017 ), providing a first, albeit fragmentary view of the complex puzzle making up the control of N utilization by plants. However, most components listed in these two articles refer to regulators acting at the gene expression level, which is certainly only part of the story. Indeed, Jacquot et al. (2017) remind us that posttranslational regulatory mechanisms also play a major role, as evidenced by the data available for N transporters in both plants and microorganisms. For instance, phosphorylation is now known to be of major importance for controlling both transport and/or sensing functions of NPF6.3 (NRT1.1) and AMT1.1 in Arabidopsis (see also Liu and von Wirén, 2017 ).

Finally, although the elucidation of N sensing and signalling mechanisms now involves sophisticated functional genomics and systems biology approaches, much remains to be done at the phenotypic level to unravel all effects of N signalling in plants, and all responses of N acquisition and utilization to environmental factors. The reviews by Lin and Tsay (2017) and Bloom and Rubio-Asensio (2017) are both excellent illustrations of this statement. Indeed, although it has been suspected for a long time that N compounds could be signal molecules controlling flowering in plants, Lin and Tsay (2017) stands as a rare example of a putative comprehensive model for explaining the effect of N availability on flowering time in Arabidopsis. On the other hand, Bloom and Rubio-Asensio (2017) address the crucial question of the negative effect that the elevation of atmospheric CO 2 concentration is predicted to have on the N status of most C 3 plants. They document in detail, in Arabidopsis and wheat, the hypothesis that this effect is dependent on the N form provided to the plant, because of a specific inhibition of the assimilation of nitrate, but not of ammonium, by elevated CO 2 .

How can the fundamental knowledge acquired in model plants be used to speed up improvement of N use efficiency in crops? This is now a major question being addressed by many groups working on inorganic N utilization. Fan et al. (2017) and Li et al. (2017) review recent developments associated with this goal. As a consequence of our now detailed knowledge on the ammonium and nitrate transporter genes (see above), many attempts have been based on the manipulation of their expression, but there are only limited examples of success using this strategy to improve root N uptake in crops. The reasons for this are still unclear, but the selection of appropriate gene promoters may be crucially important in ensuring a positive outcome ( Fan et al. , 2017 ; Li et al. , 2017 ); another reason may be related to the differences between species ( Li et al. , 2017 ). Surprisingly, overexpression of nitrate transporter genes yielded better results in rice than in Arabidopsis, even though nitrate is not considered to be the preferred N source for rice. One of the best examples is the overexpression of the OsNRT2.3b gene in rice, which significantly enhanced growth, grain yield and N use efficiency, but through a mechanism more related to control of pH than direct stimulation of nitrate transport ( Fan et al. , 2016 ). However, the hypothesis that ammonium or nitrate transporters are key players in determining N use efficiency is supported by quantitative genetic studies. This is exemplified by the finding that polymorphism in the OsNRT1.1B nitrate transporter gene is causal in the marked difference in N use efficiency between japonica and indica subspecies of rice ( Hu et al. , 2015 ). Besides ammonium and nitrate transport, other processes of N utilization, such as N remobilization during senescence and protein accumulation in grains, or developmental traits such as root architecture, are also crucial for determining N use efficiency ( Havé et al. , 2017 ; Hawkesford, 2017 ). Accordingly, several reports indicate that manipulation of organic N transport and allocation between organs is also a promising strategy for improving crop productivity ( Tegeder, 2014 ).

Recent years have seen a tremendous increase in the number of genes found to be involved in the mechanisms of inorganic N utilization in plants, especially relating to signalling. Important pieces of the puzzle are still missing, such as regulators acting at the posttranslational level. However, based on our current knowledge there are at least four key pathways for future research.

First, we now need to understand how all these genes interact within the complex regulatory networks allowing plants to ensure adequate N nutrition under fluctuating environmental conditions. Working with so many genes at the same time will require high-throughput phenotyping methodologies for large-scale functional characterization studies, dedicated methods for investigating gene networks at the tissue-specific level, and mathematical modelling for understanding, and in the long term predicting, the functioning of these networks.

Second, there are now interesting parallels emerging between the regulatory mechanisms involved in the control of nitrate and/or ammonium acquisition and those involved in the control of symbiotic N 2 -fixation. For instance, NIN-like transcription factors are pivotal in the regulation of short-term responses to nitrate in Arabidopsis ( Marchive et al. , 2013 ) and of nodulation in legumes ( Schauser et al. , 2005 ). Also, a similar system of peptide signalling seems to be operating in the regulation of root nitrate uptake in Arabidopsis ( Tabata et al. , 2014 ) and lateral root and nodule development in Medicago ( Mohd-Radzman et al. , 2016 ). This clearly calls for more integrated studies of the various pathways of N acquisition in plants, and thus for more interactions between the two communities working on inorganic N assimilation and symbiotic N 2 fixation.

Third, biotechnological attempts to manipulate candidate genes for improving N use efficiency in crops should be pursued, but using more refined methods (e.g. dedicated gene promoters, genome editing technologies, gene stacking). This is particularly important as our exploding knowledge about N signalling pathways is expected to provide an unprecedented number of new candidate genes. In fact, several examples confirm that altering the expression of regulators of N transporters (such as NAC or BT transcription factors) can lead to improved plant performance ( Fan et al. , 2017 ; Li et al. , 2017 ). Furthermore, identifying beneficial alleles of key genes of N utilization is important. For selecting genotypes better adapted to low N input production systems, this will certainly require in-depth analysis of wild or ancient germplasms ( Hawkesford, 2017 ).

Finally, scientists working on N nutrition of plants need to worry about climate change, and for at least two reasons. On the one hand, it is probably of strategic importance to understand why elevated atmospheric CO 2 concentration is predicted to be so detrimental for the N status of most crops which are basic to human nutrition, with a reduction in protein content of edible parts that can be as high as 15–20% ( Loladze, 2014 ; Myers et al. , 2014 ; Bloom and Rubio-Asensio, 2017 ). On the other hand, it also appears that N availability will be one major limiting factor preventing full stimulation of yield by elevated CO 2 in C 3 species ( Reich et al. , 2006 ), yet more reason for improved N use efficiency in plants.

I sincerely thank Raquel Gonzalez-Cuesta, Jonathan Ingram, David Mansley, Mary Traynor and Bennett Young for their help in editing this special issue of Journal of Experimental Botany .

Bellegarde F , Gojon A , Martin A . 2017 . Signals and players in the transcriptional regulation of root responses by local and systemic N signaling in Arabidopsis thaliana . Journal of Experimental Botany 68 , 2553 – 2565 .

Google Scholar

Bouguyon E , Brun F , Meynard D et al.  2015 . Multiple mechanisms of nitrate sensing by Arabidopsis nitrate transceptor NRT1.1 . Nature Plants 1 , 15015 .

Calatrava V , Chamizo-Ampudia A , Sanz-Luque E , Ocaña-Calahorro F , Llamas A , Fernandez E , Galvan A . 2017 . How Chlamydomonas handles nitrate and the nitric oxide cycle . Journal of Experimental Botany 68 , 2593 – 2602 .

Castro-Rodríguez V , Cañas RA , de la Torre FN , Pascual MB , Avila C , Cánovas FM . 2017 . Molecular fundamentals of nitrogen uptake and transport in trees . Journal of Experimental Botany 68 , 2489 – 2500 .

Fan X , Naz M , Fan X , Xuan W , Miller AJ , Xu G . 2017 . Plant nitrate transporters: from gene function to application . Journal of Experimental Botany 68 , 2463 – 2475 .

Fan X , Tang Z , Tan YW et al.  2016 . Overexpression of a pH-sensitive nitrate transporter in rice increases crop yields . Proceedings of the National Academy of Sciences, USA 113 , 7118 – 7123 .

Forde BG , Gent L . 2017 . How do plants sense their nitrogen status ? Journal of Experimental Botany 68 , 2531 – 2540 .

Forde B , Lea P , Zhang H . 2007 . Preface (Nitrogen nutrition) . Journal of Experimental Botany 58 , iv.

Galloway JN , Aber JD , Erisman JW , Seitzinger SP , Howarth RW , Cowling EB , Cosby BJ . 2003 . The nitrogen cascade . Bioscience 53 , 341 – 356 .

Gilliham M . 2011 . Preface (Plant membrane biology) . Journal of Experimental Botany 62 , 2231 – 2232 .

Gojon A , Krouk G , Perrine-Walker F , Laugier E . 2011 . Nitrate transceptor(s) in plants . Journal of Experimental Botany 62 , 2299 – 2308 .

Hachiya T , Sakakibara H . 2017 . Interactions between nitrate and ammonium in their uptake, allocation, assimilation, and signaling in plants . Journal of Experimental Botany 68 , 2501 – 2512 .

Havé M , Marmagne A , Chardon F , Masclaux-Daubresse C . 2017 . Nitrogen remobilization during leaf senescence: lessons from Arabidopsis to crops . Journal of Experimental Botany 68 , 2513 – 2529 .

Hawkesford MJ . 2017 . Genetic variation in traits for nitrogen use efficiency in wheat . Journal of Experimental Botany 68 , 2627 – 2632 .

Hirel B , Le Gouis J , Ney B , Gallais A . 2007 . The challenge of improving nitrogen use efficiency in crop plants: towards a more central role for genetic variability and quantitative genetics within integrated approaches . Journal of Experimental Botany 58 , 2369 – 2387 .

Holsbeeks I , Lagatie O , Van Nuland A , Van de Velde S , Thevelein JM . 2004 . The eukaryotic plasma membrane as a nutrient-sensing device . Trends in Biochemical Sciences 29 , 556 – 564 .

Hu B , Wang W , Ou S et al.  2015 . Variation in NRT1.1B contributes to nitrate-use divergence between rice subspecies . Nature Genetics 47 , 834 – 838 .

Jacquot A , Li Z , Gojon A , Schulze W , Lejay L . 2017 . Post-translational regulation of nitrogen transporters in plants and microorganisms . Journal of Experimental Botany 68 , 2567 – 2580 .

Krapp A , David LC , Chardin C et al.  2014 . Nitrate transport and signaling in Arabidopsis . Journal of Experimental Botany 65 , 789 – 798 .

Lezhneva L , Kiba T , Feria-Bourrellier AB , Lafouge F , Boutet-Mercey S , Zoufan P , Sakakibara H , Daniel-Vedele F , Krapp A . 2014 . The Arabidopsis nitrate transporter NRT2.5 plays a role in nitrate acquisition and remobilization in nitrogen-starved plants . The Plant Journal 80 , 230 – 241 .

Li H , Hu B , Chu C . 2017 . Nitrogen use efficiency in crops: lessons from Arabidopsis and rice . Journal of Experimental Botany 68 , 2477 – 2488 .

Lima JE , Kojima S , Takahashi H , von Wirén N . 2010 . Ammonium triggers lateral root branching in Arabidopsis in an AMMONIUM TRANSPORTER1;3-dependent manner . The Plant Cell 22 , 3621 – 3633 .

Lin YL , Tsay YF . 2017 . Influence of differing nitrate and nitrogen availability on flowering control in Arabidopsis . Journal of Experimental Botany 68 , 2603 – 2609 .

Liu Y , von Wirén N . 2017 . Ammonium as a signal for physiological and morphological responses in plants . Journal of Experimental Botany 68 , 2581 – 2592 .

Loladze I . 2014 . Hidden shift of the ionome of plants exposed to elevated CO2 depletes minerals at the base of human nutrition . eLIFE 3 , e02245 .

Marchive C , Roudier F , Castaings L , Bréhaut V , Blondet E , Colot V , Meyer C , Krapp A . 2013 . Nuclear retention of the transcription factor NLP7 orchestrates the early response to nitrate in plants . Nature Communications 4 , 1713 .

Mohd-Radzman NA , Laffont C , Ivanovici A , Patel N , Reid D , Stougaard J , Frugier F , Imin N , Djordjevic MA . 2016 . Different pathways act downstream of the CEP peptide receptor CRA2 to regulate lateral root and nodule development . Plant Physiology 171 , 2536 – 2548 .

Myers SS , Zanobetti A , Kloog I et al.  2014 . Increasing CO 2 threatens human nutrition . Nature 510 , 139 – 142 .

O’Brien JA , Vega A , Bouguyon E , Krouk G , Gojon A , Coruzzi G , Gutiérrez RA . 2016 . Nitrate transport, sensing, and responses in plants . Molecular Plant 9 , 837 – 856 .

Ohkubo Y , Tanaka M , Tabata R , Ogawa-Ohnishi M , Matsubayashi Y . 2017 . Shoot-to-root mobile polypeptides involved in systemic regulation of nitrogen acquisition . Nature Plants 3 , 17029 .

Reich PB , Hobbie SE , Lee T , Ellsworth DS , West JB , Tilman D , Knops JM , Naeem S , Trost J . 2006 . Nitrogen limitation constrains sustainability of ecosystem response to CO 2 . Nature 440 , 922 – 925 .

Riveras E , Alvarez JM , Vidal EA , Oses C , Vega A , Gutiérrez RA . 2015 . The calcium ion is a second messenger in the nitrate signaling pathway of Arabidopsis . Plant Physiology 169 , 1397 – 1404 .

Bloom AJ , Rubio-Asensio JS . 2017 . Inorganic nitrogen form: a major player in wheat and Arabidopsis responses to elevated CO 2 . Journal of Experimental Botany 68 , 2611 – 2625 .

Saez CA , Canton FR , Forde BG . 2012 . Preface (Nitrogen use efficiency in plants) . Journal of Experimental Botany 63 , 4993 .

Sakakibara H , Hase T , Yamaya T . 2011 . Preface (Nitrogen: molecular biology, ecophysiology and beyond) . Journal of Experimental Botany 62 , 1347 .

Schauser L , Wieloch W , Stougaard J . 2005 . Evolution of NIN-like proteins in Arabidopsis, rice, and Lotus japonicus . Journal of Molecular Evolution 60 , 229 – 237 .

Steffen W , Richardson K , Rockstorm J et al.  2015 . Planet boundaries: Guiding human development on a changing planet . Science 347 , 1259855 .

Tabata R , Sumida K , Yoshii T , Ohyama K , Shinohara H , Matsubayashi Y . 2014 . Perception of root-derived peptides by shoot LRR-RKs mediates systemic N-demand signaling . Science 346 , 343 – 346 .

Takahashi H . 2014 . Preface (Nutrient sensing and signalling) . Journal of Experimental Botany 63 , 767 – 768 .

Tegeder M . 2012 . Transporters for amino acids in plant cells: some functions and many unknowns . Current Opinion in Plant Biology 15 , 315 – 321 .

Tegeder M . 2014 . Transporters involved in source to sink partitioning of amino acids and ureides: opportunities for crop improvement . Journal of Experimental Botany 65 , 1865 – 1878 .

Undurraga SF , Ibarra-Henríquez C , Fredes I , Miguel-Álvarez JM , Gutiérrez RA . 2017 . Nitrate signaling and early responses in Arabidopsis roots . Journal of Experimental Botany 68 , 2541 – 2551 .

Yuan L , Loqué D , Kojima S , Rauch S , Ishiyama K , Inoue E , Takahashi H , von Wirén N . 2007 . The organization of high-affinity ammonium uptake in Arabidopsis roots depends on the spatial arrangement and biochemical properties of AMT1-type transporters . The Plant Cell 19 , 2636 – 2652 .

Zhang X , Davidson EA , Mauzerall DL , Searchinger TD , Dumas P , Shen Y . 2015 . Managing nitrogen for sustainable development . Nature 528 , 51 – 59 .

Email alerts

Citing articles via.

• Recommend to your Library

Affiliations

• Online ISSN 1460-2431
• Print ISSN 0022-0957
• Copyright © 2024 Society for Experimental Biology
• About Oxford Academic
• Publish journals with us
• University press partners
• What we publish
• New features  
• Open access
• Institutional account management
• Rights and permissions
• Get help with access
• Accessibility
• Advertising
• Media enquiries
• Oxford University Press
• Oxford Languages
• University of Oxford

Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide

• Copyright © 2024 Oxford University Press
• Cookie settings
• Cookie policy
• Privacy policy
• Legal notice

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

• Nutrition in Plants

Do plants go on a diet? Do they have to bother about the kind of nutrition that they are taking? If you have ever wondered about how nutrition in plants occurs, then you are at the right place. Dive in to extract more information!

Suggested Videos

Every living organism needs some kind of energy and nutrient materials to ensure that the life processes go on smoothly. Moreover, this energy requirement is got from the food.  You can understand this better in animals and human beings as you see it on a daily basis. You very well know what happens if you skip breakfast or lunch! But what about plants? Do they require any nutrition at all?

Browse more Topics under Life Processes

• Nutrition in Animals
• Respiration
• Transportation in Plants
• Transportation in Human Beings

Plants and their Nutrition Requirements

Plants are also living things that need some form of energy. They have cells and tissues . They also grow in size and girth. And they are the producers of the ecosystem . So, in order to synthesize food, they do have nutrient requirements. Of course, the kind of nutrient requirements varies.

This kind of nutrition in plants is called the autotrophic mode of nutrition. What does this actually mean? It means that plants have the special capability to make their own food, by using simple inorganic substances to produce organic molecules/substances. They get the energy sources from non-living things such as sun and carbon dioxide.

Plants also have chlorophyll in them, the green colour pigment. With the help of all these above factors, plants can produce simple carbohydrates. The carbohydrates thus produced are utilized by the plant and gives it energy. When there is an excess of carbohydrates in the plants, then it is stored as a reserve for later use.

Types of Autotrophic Nutrition

According to the type of energy source used, autotrophic nutrition in plants can be of two types. They are Photo-autotrophic nutrition (where sunlight is the energy source) and Chemo-autotrophic nutrition (where chemicals are the energy source).

Learn more about the Nutrition in Animals .

The Process of Photosynthesis in Autotrophs/Plants

To put it simply, plants require certain raw materials, in order to make their own food. These raw materials include carbon dioxide, water, and sunlight . Plants get water from the soil that enters through the roots. And sunlight is the source of energy. But how does carbon dioxide enter the plants? You should first understand that carbon dioxide is a gas.

You have learned in your earlier classes that plants have openings called stomata. Guard cells surround these stomata. These stomata are the openings through which carbon dioxide enters the plants. Gaseous exchange i.e. the exchange of carbon dioxide and oxygen in plants occurs through these stomatal openings.

Water is also lost through the transpiration process through these openings. And hence, when the carbon dioxide requirement is met with for photosynthesis , plants close the stoma.

The above equation shows the chemical reactions that occur during photosynthesis.

Chlorophyll is present in structures called chloroplasts. They are disc-shaped organelles that are present in the mesophyll cells of the leaves. These help in trapping the sunlight within the plant. As the carbon dioxide enters the plant through the stoma, the light energy converts into chemical energy, by the splitting of the water molecules of the plants. Simple carbohydrates are produced in this process. Oxygen is a byproduct of photosynthesis.

In this way, plants are able to take up simple inorganic substances and convert them into simple carbohydrates, to meet their nutrient requirements.

Solved Question For You

Q: What is the site of Photosynthesis in plants? Explain briefly.

Ans: Chloroplasts are the disc-shaped cell organelles that have chlorophyll pigment in them. Photosynthesis occurs at this site in the plants. These cell organelles are present in the mesophyll tissue of the leaves. Their position is strategic in the leaves, as they can absorb the maximum amount of sunlight

Customize your course in 30 seconds

Which class are you in.

Life Processes

• Transportation In Human Beings
• Nutrition In Animals

2 responses to “Nutrition in Plants”

Am in form 1. Age 14

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Download the App

Along with Stanford news and stories, show me:

• Student information
• Faculty/Staff information

We want to provide announcements, events, leadership messages and resources that are relevant to you. Your selection is stored in a browser cookie which you can remove at any time using “Clear all personalization” below.

Your diet is one of the first places to start if you’re looking to manage your health and weight. Focusing on whole foods from plant sources can reduce body weight, blood pressure and risk of heart disease, cancer and diabetes — and it can make your environmental impact more sustainable.

But how do we embrace plants in our diets if we’re so accustomed to including meat and dairy as primary nutrition sources?

We spoke with Dr. Reshma Shah, a physician, plant-based eating advocate, co-author of “Nourish: The Definitive Plant-Based Nutrition Guide for Families” and Stanford Healthy Living instructor, about simple ways to incorporate more plants into your diet and the benefits this can provide for both you and the planet.  

Focus on whole, minimally processed foods.

People use many different terms to describe a plant-based diet, including vegetarian, lacto-ovo vegetarian, pescatarian, and flexitarian to name a few. The most restrictive is veganism, which  excludes all animal products, including meat, eggs and dairy. 

While there are health benefits to adopting a vegan diet, highly processed foods with little to no nutritional value, like Oreos or French fries, could still be a legitimate part of a vegan diet.

In contrast, a whole-foods, plant-based (WFPB) diet: 

• Emphasizes whole, minimally processed foods
• Limits or avoids animal products
• Focuses on plant nutrients from vegetables, fruits, whole grains, legumes, seeds and nuts 
• Limits refined foods like added sugar, white flour and processed oils 

Recommendations from organizations including the U.S. Dietary Guidelines for Americans, World Health Organization, American Diabetes Association and American Cancer Society tout the benefits of plant-based whole foods and caution against high amounts of red and processed meats, saturated fats, highly refined foods and added sugar. 

The vast majority of what nutritional experts are saying reflects the mantra made famous by Michael Pollen in his book “The Omnivore’s Dilemma” — eat food, mostly plants, not too much . 

Eating a plant-based diet helps the environment.

According to a report by the U.S. Food and Agriculture Organization, “The meat industry has a marked impact on a general global scale on water, soils, extinction of plants and animals, and consumption of natural resources, and it has a strong impact on global warming.” 

The meat and dairy industries alone use one third of the Earth’s fresh water , with a single quarter-pound hamburger patty requiring 460 gallons of water — the equivalent of almost 30 showers — to produce.

Reducing your meat and dairy consumption, even by a little, can have big impacts. If everyone in the U.S. ate no meat or cheese just one day a week, it would have the same environmental impact as taking 7.6 million cars off the road.

Plant-based diets prevent animal cruelty. 

Ninety-four percent of Americans agree that animals raised for food deserve to be free from abuse and cruelty , yet 99% of those animals are raised in factory farms, many suffering unspeakable conditions . 

If you would like to lessen your meat and dairy consumption due to animal welfare concerns but aren’t ready to eliminate all animal products from your diet, then you can start by taking small steps, like going meatless one day a week or switching to soy, almond or oat milk. Shah admits that initially she was not ready to give up animal products entirely. 

“I think it is a process and recommend that people go at the pace that feels comfortable for them.” 

Plant-based diets include all nutrients — even protein.

According to the American Dietetic Association, “appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, and for athletes.”

Shah says that there are a few key nutrients that strict vegans and vegetarians should keep in mind, including B12, iron, calcium, iodine, omega-3 fatty acids and vitamin D, but all of these can be obtained through plant-based foods, including fortified plant-based milks, fresh fruits and vegetables or supplemental vitamins, if needed. 

“I think the number one concern for people is that they won’t be able to get enough protein eating a plant-based diet. I also think that people widely overestimate the amount of protein they need.”

All plant foods contain the nine essential amino acids required to make up the proteins you need, and many vegetarian foods like soy, beans, nuts, seeds and non-dairy milk products have comparable amounts of protein to animal foods. 

“Ninety-seven percent of Americans meet their daily protein requirements, but only 4% of Americans meet their daily fiber requirements . I’ve never treated a patient for protein deficiency. If you eat a wide variety of foods and eat enough calories, protein should not be a concern.”

Savor the flavor of plant-based foods. 

Adopting a plant-based diet does not mean subsisting on boring, tasteless food. Shah enjoys incorporating flavorful, varied dishes from around the world, including Ethiopia, Thailand and her native India. 

To get started on your plant-forward journey:

• Start small: Start with adding a “Meatless Monday” to your meal plan and investigate one simple and delicious recipe to try each week. Once you have identified a few favorites, you can add them to your rotation and maybe go meatless one or two days a week. You can learn a few easy techniques to incorporate in many dishes, like roasting vegetables or blending quick and easy soups. 
• Change your plate proportions: Instead of giving up your meat-based protein completely, try to reduce the space it takes on your plate. Instead of a quarter-pound sirloin steak or a full serving of roasted chicken, try a vegetable-heavy stir-fry with a few slices of beef or a salad with chicken. Once your palate and mindset have adjusted to the smaller quantity of meat, try replacing it occasionally with plant-based proteins like tofu, seitan or beans.  
• Be prepared when dining out: If possible, try to examine the restaurant menu ahead of your meal, so you’ll arrive with a plan of what you can eat. Ask for the vegan options and don’t be afraid to request substitutions or omissions for your dish. Fortunately, with more people choosing a vegetarian lifestyle, many restaurants now provide tasty, meat-free options to their customers. 
• Share a dish: Bring a dish to share at a party or potluck; this will lessen your worries about food options. Let your host know ahead of time that you are planning on bringing a dish or, if that is not possible, be upfront and find out if any modifications can be made to accommodate your preferences. Often a simple solution can be found with a little advanced planning.
• Accommodate family members: It can be tricky when one family member is ready to commit to a new diet and lifestyle while others are not. Shah recommends approaching this situation compassionately and allowing for flexibility, if possible. Hopefully your family will be willing to support you even if they are not ready to make the same commitments. Communication is key, and Shah says that the conversation is over the minute someone feels judged, so try to look for points of compromise to reach an amicable solution. 
• Feeling satisfied: A diet of nothing but lettuce and vegetables will leave you feeling hungry and unfulfilled. Be sure to bulk up your meals with filling, fiber-rich whole grains, plant-based proteins and healthy fats. Plant-based meat substitutes like Beyond Beef, seitan and veggie burgers can also be a satisfying choice when you are craving your favorite meat-based comfort food.

Remember that small, consistent changes can add up to big benefits for your health and the planet. Treat yourself and others with compassion as you embrace this new lifestyle, and take time to enjoy the different flavors and textures you discover in your journey.

“It is a really delicious, healthful, sustainable and compassionate way of eating. It doesn’t have to be perfect. Just start simply, do what feels comfortable for you and your family, and don’t forget to celebrate the joy of eating and connection around food.” 

Dr. Reshma Shah will be teaching a plant-based online cooking class with Healthy Living this summer on Tuesday, July 13, from 4:00 – 5:30 p.m.

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518108/
• https://www.sciencedirect.com/science/article/pii/S2212371713000024 
•  https://www.portland.gov/water/water-efficiency-programs/save-water-home 
•   https://water.usgs.gov/edu/activity-watercontent.php  
• https://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/reducing-your-footprint/)  
• https://www.aspca.org/about-us/press-releases/aspca-research-shows-americans-overwhelmingly-support-investigations-expose 
•  https://www.sentienceinstitute.org/us-factory-farming-estimates
•  https://pubmed.ncbi.nlm.nih.gov/19562864/ 
•   https://www.ars.usda.gov/ARSUserFiles/8040053 0/pdf/0102/usualintaketables2001-02.pdf

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List

Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function

Consumer demand for plant protein-based products is high and expected to grow considerably in the next decade. Factors contributing to the rise in popularity of plant proteins include: (1) potential health benefits associated with increased intake of plant-based diets; (2) consumer concerns regarding adverse health effects of consuming diets high in animal protein (e.g., increased saturated fat); (3) increased consumer recognition of the need to improve the environmental sustainability of food production; (4) ethical issues regarding the treatment of animals; and (5) general consumer view of protein as a “positive” nutrient (more is better). While there are health and physical function benefits of diets higher in plant-based protein, the nutritional quality of plant proteins may be inferior in some respects relative to animal proteins. This review highlights the nutritional quality of plant proteins and strategies for wisely using them to meet amino acid requirements. In addition, a summary of studies evaluating the potential benefits of plant proteins for both health and physical function is provided. Finally, potential safety issues associated with increased intake of plant proteins are addressed.

1. Introduction

Protein is a nutrient that has been trending increasingly positive in the minds of consumers, with demand rising for both plant and animal sources of protein [ 1 ]. In addition, there is a growing body of clinical evidence, especially in older adults, supporting health benefits associated with protein at or above current dietary protein intake recommendations. Among these health benefits are increases in lean body mass [ 2 , 3 , 4 , 5 , 6 ], functional benefits such as increased leg power [ 4 ] or gait speed [ 6 ], and improved bone density [ 7 , 8 , 9 ]. Thus, on the one hand, there is likely to be a continued push for protein-rich options in the food marketplace. On the other hand, the global production of an increased volume of food protein, especially high-quality animal protein, could present environmental sustainability challenges. The production of 1 kg of high-quality animal protein requires feeding 6 kg plant protein to livestock, which introduces the subsequent strain on land and water resources, as well as potential increases in greenhouse gas emissions, associated with livestock agriculture [ 1 , 10 ]. Wider and prudent use of plant proteins in the diet can help to supply adequate high-quality protein for the population and may reduce the potential for adverse environmental consequences. This review presents information on: (1) the nutritional quality of plant proteins; (2) strategies for wisely using plant proteins to meet indispensable amino acid requirements; (3) effects of plant proteins on health and physical function; and (4) potential health and safety concerns associated with plant proteins.

2. Determination of Protein Quality

Two requirements for a protein to be considered high quality, or complete, for humans are having adequate levels of indispensable amino acids (see Table 1 ) to support human growth and development and being readily digested and absorbed.

Indispensable, dispensable, and conditionally indispensable amino acids in the human diet. Adapted from [ 11 ].

Various methods for evaluating protein quality have been developed over the years, but amino acid scoring is currently the recommended method by the Food and Agricultural Organization of the United Nations (FAO) and the U.S. National Academy of Sciences [ 11 , 12 ]. The Protein Digestibility Corrected Amino Acid Score (PDCAAS) was developed in 1989 by a Joint FAO/WHO Expert Consultation on Protein Quality Evaluation [ 13 ] to compare the indispensable amino acid content of a test protein (mg/g protein) to a theoretical reference protein thought to meet indispensable amino acid requirements (mg/g protein) for a given age group, creating a ratio known as the amino acid or chemical score. The indispensable amino acid with the lowest ratio is referred to as the most limiting amino acid. The most limiting amino acid score is corrected for the fecal true digestibility of the protein. To determine fecal true protein digestibility, rats are fed a known amount of nitrogen from the test protein and then fecal nitrogen excretion is measured [ 14 ]. This measure represents apparent protein digestibility. The fecal nitrogen excretion from the rats on a protein-free diet is then subtracted from fecal nitrogen excretion on the test protein, which accounts for non-dietary protein nitrogen excretion from bacterial cells and digestive secretions. The result is referred to as true fecal protein digestibility. The calculation equation for the PDCAAS is shown in Figure 1 .

Calculation of the PDCAAS (adapted from [ 15 ]).

The results can be expressed as either decimals or multiplied by 100 to be expressed as a percent. A PDCAAS of <1.00 indicates that the protein is suboptimal and PDAAS scores >1.00 are truncated to 1.00.

In 2011, the FAO introduced an updated amino acid scoring system, the Digestible Indispensable Amino Acid Score (DIAAS) [ 16 ]. The DIAAS is calculated and interpreted similarly to the PDCAAS, but with a few important differences. First, the reference patterns for the indispensable amino acids were revised to reflect advances in the scientific knowledge regarding amino acid requirements. Second, a single estimate of fecal protein digestibility is no longer used. Rather, the concept of the ileal individual amino acid digestibility was incorporated. True fecal digestibility of protein, which is based on nitrogen excretion in the feces, is complicated by the considerable exchange of protein, amino acids, and urea between systemic pools and the lower gastrointestinal tract. In response to this limitation, it was recommended to measure ileal amino acid digestibility, which reflects the concentration of amino acids that reaches the ileum and would hence enter the colon, derived from ileostomy output studies conducted in animals or humans. As such, each indispensable amino acid from a given protein source will have an associated ileal digestibility value and its amino acid score will be corrected for that value. Finally, unlike the PDCAAS, the DIAAS method allows for scores >1.00 to acknowledge that there may be incremental health benefits associated with these higher DIAAS scores.

3. The Quality of Plant Proteins

In general, most animal-based protein sources, such as milk, whey, casein, eggs, and beef, have PDCAAS at or very near 1.00 [ 13 , 17 , 18 ]. As such, they are generally considered complete protein sources for supporting indispensable amino acid requirements for human growth and development. Plant proteins, however, may have insufficient levels of one or more indispensable amino acids. Legumes are frequently low in the sulfur-containing amino acids methionine and cysteine, while lysine is typically limiting in grains [ 19 ]. However, it should be noted that plant proteins differ regarding the amounts of limiting amino acids that are present. Table 2 shows the PDCAAS and DIAAS ratings for milk protein, whey, and several selected plant protein sources. Similar to milk protein and whey, soy protein essentially has a PDCAAS of 1.00, and four more proteins (canola, potato, pea, and quinoa) have a PDCAAS of at least 0.75.

Protein quality of whey and selected vegetable protein sources.

1 FAO FN Paper 51 1989, ages 2–5 year, AA ref standard (mg/g protein) [ 13 ]: His 19, Ile 28, Leu 66, Lys 58, SAA 25, AAA 63, Thr 34, Trp 11, Val 35. 2 IOM 2002/2005, ages 1+ year, AA ref standard (mg/g protein) [ 11 ]: His 18, Ile 25, Leu 55, Lys 51, SAA 25, AAA 47, Thr 27, Trp 7, Val 32. 3 FAO FN Paper 92 2011, ages 0.5–3 year, AA ref standard (mg/g protein) [ 16 ]: His 20, Ile 32, Leu 66, Lys 57, SAA 27, AAA 52, Thr 31, Trp 8.5, Val 43. 4 FAO FN Paper 92 2011, older child, adolescent, adult, AA ref standard (mg/g protein) [ 16 ]: His 16, Ile 30, Leu 61, Lys 48, SAA 23, AAA 41, Thr 25, Trp 6.6, Val 40. PDCAAS, Protein Digestibility Corrected Amino Acid Score; DIAAS, Digestible Indispensable Amino Acid Score; AA, amino acid; His, histidine; Ile, isoleucine; Leu, leucine; Lys, lysine; SAA, sulfur amino acids (methionine and cysteine); AAA, aromatic amino acids (phenylalanine and tyrosine); Thr, threonine; TRP, tryptophan; Val, valine; PI, protein isolate; PC, protein concentrate; bld, boiled; ckd, cooked; cnd, canned; drnd, drained. * Limiting amino acid by all four amino acid reference standards.

While the PDCAAS of most plant proteins may be less than 1.00, the individualized protein scoring system is only one way to evaluate the potential contributions of a protein to the diet. Canada uses a method based on the Protein Efficiency Ratio (PER), which is growth/weight gain assay on rats fed different protein sources. Health Canada provides a list of PER values for different protein foods on their website and suggests that the PER of a protein source can be estimated by multiplying the PDCAAS by 2.5 [ 58 ]. Several other factors can increase the potential contribution of plant-based proteins to meeting overall dietary protein and indispensable amino acid needs. One aspect to consider is the amount of dietary protein contributed by a specific plant protein source. In the case of plant versus animal proteins, simply consuming more of the plant protein can help to provide higher indispensable amino acid intakes. Given that many whole food sources of plant-protein are less calorie-dense than animal sources of protein, greater overall food intake is needed to meet energy requirements which, in turn, helps meet indispensable amino acid requirements. In addition, it has now become much easier for consumers to boost intake of plant proteins via the availability of multiple plant-based protein isolates and concentrates (soy, pea, canola, potato, fava, etc.) in the food industry. It was once difficult for individuals to take in relatively large amounts of protein from whole plant foods because they typically have a low percentage of protein. However, plant protein isolates and concentrates, which often contain 80% or more protein by weight, make it possible to consume 10–20 g or more of plant-based protein per one serving of a ready-to-drink shake or powder mix.

Dietary protein variety is also key for meeting indispensable amino acid requirements. While the PDCAAS of an individual protein is critical when evaluating the quality of a sole-source protein, it becomes less significant when the diet contains proteins from many sources. For example, lysine is often limiting in grain proteins, but such proteins are good sources of the sulfur-containing amino acids. On the other hand, legumes are often rich sources of lysine but are limiting in sulfur-containing amino acids. Consumption of these two protein sources over the course of the day allows them to “complement” one another, helping to meet requirements for both types of indispensable amino acids. A classic example would be a combination of pea and rice proteins. Protein blends of pea and rice ranging 40–90% pea protein can achieve a PDCAAS of 1.00, using the 2011 FAO amino acid reference pattern for adults [ 16 ]. Flexitarian approaches, in which persons consume increased amounts of plant-based proteins but also include some animal proteins, represent another strategy for helping to meet indispensable amino acid requirements. Thus, the quality of protein in the diet may be quite high if the plan is to consume a variety of plant proteins with differing amino acid profiles.

One question that has arisen for vegetarians is whether it is needed to combine complementary protein sources at the same meal. Young and Pellet [ 19 ] addressed this issue. They noted that the common limiting amino acid in grains, lysine, has a significant pool in the skeletal muscle. After a protein-rich meal, they estimated that 60% of the adult daily requirement for lysine could be stored in this pool within 3 h. If a person were to consume a lysine-poor meal within 3 h of a lysine-rich meal, there would still be adequate intracellular lysine available to promote protein synthesis. Thus, it is not necessary to consume complementary protein sources at the same meal if the gap between meals is relatively short, around 3 h; the complementary amino acids will be metabolically available for protein synthesis.

An often-neglected aspect of plant proteins is their high content of some important dispensable/conditionally indispensable amino acids. The PDCAAS method of evaluating protein quality focuses only on indispensable amino acids and generally on whole body protein requirements. However, since the development of the PDCAAS concept, the knowledge base around the health- or performance-related effects of individual amino acids, both indispensable and conditionally indispensable has grown dramatically. For example, whey protein has received much attention for muscle building due to its high level of leucine (see Figure 1 ), which serves as a nutrient signal for initiating the process of muscle protein synthesis [ 59 , 60 ]. However, it is important not to forget the vital physiologic functions of dispensable/conditionally indispensable amino acids found in large amounts in plant proteins. Soy protein, while not as high as whey in leucine, is nearly three times higher in arginine, 2–3 times higher in glutamine, and has double the glycine content ( Figure 2 and Table 3 ). Other plant proteins can be high in these amino acids as well. Arginine is necessary for the body’s synthesis of nitric oxide (vasodilator) and creatine, for urea cycle function, for regulating hormone secretion, and for immune function [ 61 , 62 ]. Glutamine is a primary fuel source for rapidly proliferating cells such as those in the immune system and gastrointestinal tract and functions in the synthesis of arginine, ornithine, and several other compounds [ 61 , 63 ]. Glycine is critical for collagen synthesis, comprising up to 1/3 of the amino acids in collagen and some studies suggest that its biosynthesis in humans may not be adequate to meet requirements [ 64 , 65 , 66 , 67 ]. Although amino acids such as arginine, glutamine, and glycine might not be classified all the time as indispensable amino acids, they perform many critical functions and plant proteins can be significant sources. Thus, the content of these dispensable/conditionally indispensable amino acids deserves to be taken into consideration when evaluating the value of plant proteins in the diet.

Comparisons of leucine and selected dispensable amino acid concentrations (mg/g protein): whey versus the Top 5 highest quality plant proteins in Table 2 .

Glutamine concentration of selected plant and dairy proteins. Sources of data: References [ 68 , 69 , 70 , 71 ] and unpublished data.

4. Importance of Plant Proteins in Health

The benefits of plant proteins on long-term health and chronic diseases have been a trending topic in recent years. This section summarizes some of the most recent evidence and analytical reviews for several target health areas, including cardiovascular health, metabolic syndrome, diabetes, cancer, renal function, lean body mass, and strength, as well as overall morbidity and mortality. This section is not meant to be a comprehensive review of the health effects of plant protein. Rather it is meant to highlight key recent studies and meta-analyses and open a dialogue to suggest future areas for research.

4.1. Plant Protein and Cardiovascular Disease and Metabolic Risk Factors

Numerous studies have explored the potential impact that dietary plant proteins have on reducing cardio-metabolic risk factors. One of the first reports to synthesize the results of plant protein intake as a substitution for animal protein was a study published in 2017. In this systematic review and meta-analysis of 112 randomized clinical trials across adults with and without hyperlipidemia, the authors demonstrated reduced markers of cardiovascular disease in favor of plant protein over animal protein consumption [ 72 ]. The authors reported a reduction in blood lipids across the studies, including lower low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B. While the authors called for higher quality randomized trials to confirm their results, this evidence supports plant protein as an effective substitution for animal protein in the diet to help reduce cardiovascular disease risk factors in adults. A more recent meta-analysis was performed on the impact of plant protein compared with animal protein across 32 intervention trials in hypercholesterolemic patients [ 73 ]. While there was evidence in favor of plant proteins to lower lipid profiles, most trials in this analysis examined soy products as the intervention compared with a variety of animal protein sources. Therefore, it may be difficult to draw a broad conclusion about all plant proteins based on the limited types of plant proteins studies and on potential confounding effects driven by other bioactive properties of soy products.

Benefits of plant proteins and metabolic health have also been described for adolescent populations. Obesity is a growing problem worldwide among adolescents, and several studies have examined the potential benefits of plant protein intake in relation to obesity, weight management, or metabolic syndrome. One such study was the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, a cross-sectional study of European adolescents [ 74 ]. In this study, both total and animal protein intake were higher in obese adolescents. Adolescents consuming higher levels of plant protein exhibited lower body fat percentages and BMI compared with those adolescents with higher animal protein intake. However, protein is critical for many physiologic functions and facets of development, and adequate protein intake is important. The study suggested increasing plant protein in adolescent diets as a substitution for animal protein to help control obesity and for its potential positive benefits for cardio-metabolic factors [ 74 ]. Incorporating more plant proteins into the diet to take the place of excess calories and animal protein may be a useful strategy to assist with adolescent obesity.

Criticism has arisen from some researchers, however, regarding the attempt to make blanket statements about the superiority of the cardio-metabolic health benefits of plant proteins versus animal proteins. While advantages of plant food sources have been described, researchers advise not to indiscriminately consider all animal proteins as inferior to plant protein for cardiovascular health, citing limited and inconsistent evidence to support that type of conclusion [ 75 , 76 ]. In an editorial, Campbell cautioned that not all studies have shown a detrimental effect of red meat compared with plant protein on cardiovascular disease risk markers and suggested there is mixed evidence when evaluating white meat as compared to red meat as a healthier animal option [ 75 ]. For example, the randomized, crossover, controlled trial by Bergeron et al. [ 77 ] found a benefit of non-meat protein intake over animal protein intake, but no difference between white meat versus red meat in the animal protein dietary periods. The study authors concluded that more plant-based protein should be introduced into the diet to reduce cardiovascular disease risk but noted that their short intervention period and inability to show a difference between various animal protein diets may limit the interpretation of results. In summary, lumping all animal proteins together as being inferior to plant proteins regarding cardiovascular disease risk is not advised. Generalizing the health benefits of plant protein over animal protein is difficult due to trial inconsistencies and limited control of variables. The overall health composition of foods should be considered instead of creating competition between animal plant-based protein sources, and a wide variety of nutritious protein-rich foods from animal and plant sources should be incorporated into the diet along with healthy dietary habits [ 75 ].

4.2. Plant Protein and Diabetes

While vegetarian diets are associated with a substantial risk reduction for diabetes [ 78 ], it is unclear if substitution of plant protein for animal protein helps to drive this risk reduction. Malik et al. [ 79 ], analyzing data from the Nurses’ Health Study II, found that substituting 5% of energy intake from vegetable protein for animal protein was associated with a 23% reduced risk of type 2 diabetes. An acute feeding of 20 g yellow pea protein, served in a tomato soup 30 min in advance of an ad libitum pizza meal, reduced the glycemic response to the pizza meal and the energy intake from the pizza meal (when compared with tomato soup not containing pea protein) [ 80 ]. In a similar study, a 400-kcal breakfast comprising a meal replacement beverage containing about 29 g soy protein was compared with an isocaloric, higher glycemic index, lower protein breakfast. The soy protein beverage was associated with: (1) lower postprandial glycemic and ghrelin responses to the breakfast; and (2) decreased postprandial insulin secretion from a standardized lunch fed 4 h later [ 81 ].

In a 2015 meta-analysis of randomized control trials that replaced animal protein sources with plant protein for at least 35% of total dietary protein intake over a median study length of eight weeks, the authors reported significant, but modest, improvements in HbA1c, fasting glucose, and fasting insulin levels in individuals with diabetes [ 82 ]. These results were positive, but limitations were noted. The authors called for longer and larger clinical trials to confirm results as sample sizes were relatively small in the studies reviewed. It should also be noted that the meta-analysis included reported studies for both type 1 and type 2 diabetic populations.

Since this meta-analysis was conducted in 2015, a prospective clinical trial evaluated the potential benefits of high protein diets using either plant or animal protein sources in adult individuals (aged 64.3 ± 1 years) with type 2 diabetes. This randomized clinical study of 37 diabetic individuals placed on either a high animal protein diet (80.2% of total protein in intervention) or a high plant protein diet (72.3% of total protein in intervention) for six weeks found that both diets similarly reduced body weight, BMI, HbA1c, and blood lipid markers after the intervention [ 83 ]. The animal protein group experienced a decrease in fasting glucose and whole-body insulin sensitivity from baseline, but there was no difference between the protein groups. Further analyses of results from this trial revealed similar responses from both intervention groups for liver fat, markers of hepatic inflammation, and insulin resistance [ 84 ]; oxidative stress biomarkers [ 85 ]; and pro-inflammatory cytokines [ 83 ]. Other studies have also failed to show a benefit of a vegetarian diet over animal protein diets for individuals with diabetes. In a randomized controlled trial in patients with type 2 diabetes, no benefits or differences were observed in cardio-metabolic biomarkers across three groups randomized to a red meat protein diet, soy legume protein diet, or a non-soy legume protein diet after eight weeks [ 86 ]. The authors concluded that impact of whole diet could be more relevant than the impact of protein source, and that animal protein could be consumed as part of a balanced diet. Larger and longer-term studies in individuals with diabetes are warranted.

4.3. Plant Protein Intake and Incidence of Cancer

Another area of interest for examining benefits of increasing plant protein intake in place of animal protein is in cancer risk reduction. Certainly, the risk for developing cancer is influenced by multiple factors, such as genetic predisposition, environment, and dietary and other lifestyle habits. One group has focused on examining the risk of colorectal cancer in individuals using gene–environment interaction analyses, incorporating several lifestyle factors, genetic factors, and cancer risk [ 87 ]. In their examination of a large, prospective Danish cohort, the authors reported an association between certain genetic polymorphisms for fatty acid metabolism and colorectal cancer, which were further associated with high meat intake. They described that high meat intake was associated with high risk of colorectal cancer among some gene carriers compared with those having the same genetic polymorphism who consumed diets with lower meat intake [ 87 ]. Therefore, substituting plant protein for animal protein in the diet may be a strategy to lower the risk of colorectal cancer in individuals with certain gene variants. There have been mixed results, however, regarding whether shifting from animal protein to more plant protein will reduce colorectal cancer risk. For example, a recent study included 79 pre-diabetic adults on a one-year weight-loss dietary intervention [ 88 ]. This study examined total dietary protein intake, red meat intake, and animal to plant protein ratio. At baseline and after the one-year intervention, these dietary habits were compared with the level of fecal ammonia concentrations, a biomarker for colorectal cancer risk. While this study did report a dose-dependent association between fecal ammonia concentration and the amount of red meat intake, there was no associations between fecal ammonia and total protein intake or the ratio of animal to plant protein in these individuals [ 88 ].

In our review of the literature, there was limited evidence to confirm the benefits of plant protein above animal protein on its impact on cancer risk reduction. This will likely be a growing area of focus for future research to better understand if plant protein itself confers any benefits or whether the adoption of better dietary habits associated with increased plant protein intake helps to drive favorable health outcomes.

4.4. Plant Proteins as Functional Foods

Plant proteins have also been studied for their potential as functional foods. Numerous studies have been conducted to examine the impact on cardiovascular risk, glycemia, or satiety. Many studies have focused on the functional and bioactive properties of soy protein, especially for reducing cardiovascular disease risk, modulating inflammation, or modulating the immune system [ 89 ]. A recent systematic review examined the bioactive properties of plant protein sources other than soy, including protein from pea, lupin, fava bean, rice, oat, hemp, and lentil [ 90 ]. Most trials reported the benefits of plant protein ingredients by examining postprandial concentrations of blood glucose, insulin, and/or appetite regulating hormones. While there was heterogeneity in results, studies that compared animal to plant protein showed no benefit of plant protein on regulating postprandial glycemia. Similarly, the benefits of plant protein as a functional food for satiety showed mixed results, although there may be some benefit to pea protein. It is likely that the bioactive components of a plant diet are often attributed to whole food sources than isolated protein. It is well known that numerous components in plants, such as carotenoids and flavonoids, confer bioactive benefits for health. However, further research on plant proteins and bioactive peptides is needed.

4.5. Plant Protein Intake and Its Relationship to Mortality

Many studies have also linked sources of protein intake to mortality. A recent publication from the large, prospective cohort from the NIH-AARP Diet and Health Study also examined the impact of dietary protein choice on mortality [ 91 ]. In this study, 617,199 individuals aged 50–71 across the U.S. were followed from 1995 or 1996 until study follow-up in December 2011. Intake of plant protein was significantly inversely associated with all-cause mortality as well as cause-specific mortality from cardiovascular disease and stroke in both males and females. They reported that replacement of just 3% of protein intake with plant protein versus animal was associated with a 10% reduction in overall mortality across both men and women [ 91 ]. These results are consistent with a recent systematic review and meta-analysis on the impact of protein intake on mortality risk [ 92 ]. Aligned with other reports highlighting the importance of increased protein intake, especially as we age, higher total protein intake was associated with a reduced all-cause mortality risk. Stratifying data into animal protein intake versus plant protein intake, however, revealed a lower all-cause mortality risk for those consuming plant protein diets. Ten studies examining animal or plant protein intake were analyzed in the meta-analysis for the association with mortality from cardiovascular disease. While there was no clear association between animal protein intake and mortality, an inverse association was found between plant protein intake and cardiovascular disease risk. These studies support a benefit of substituting more plant protein into the diet in place of animal protein in terms of longevity and mortality.

4.6. Renoprotective Effect of Plant Proteins

The American diet is typically characterized as low in fruits, vegetables, dairy, and healthy oils and exceeds recommendations for total grains, total protein foods, added sugar, saturated fats, and sodium [ 93 ]. This diet, also characterized as the Western diet, has been under scrutiny to establish the metabolic differences that contribute to chronic disease, especially regarding chronic kidney disease (CKD) [ 94 ]. Recent epidemiological evidence suggests that not only the amount of protein, but also the origin of protein (e.g., plant vs. animal), may be a factor that influences kidney function [ 95 ]. The nuances of earlier experimentation with low versus normal recommended protein intake lent clues to the potential impact of protein origin. Viberti et al. [ 96 ] replaced the animal protein in an isocaloric diet with vegetable sources in a crossover study with healthy adults and observed a reduction in glomerular filtration rate (GFR) and renal plasma flow (RPF). A sub-study within a broader investigation that was designed to examine the effect of dietary protein on GFR compared healthy vegetarian subjects with those on an omnivorous diet. Both groups ate their normal diets ab libitum. The mean plasma creatinine level was not significantly different between groups, but the creatinine clearance was significantly lower in the vegetarian group [ 97 ]. A soy protein-rich diet was found to reduce glomerular hyperfiltration in a study of patients with type 1 diabetes with early stage nephropathy [ 98 ]. Increases in GFR and glomerular hyperfiltration contribute to the incidence of kidney injury and indicate how diet can have a negative impact on kidney function [ 99 ].

The effect of plant and animal protein intake on renal function continues to be explored. In a prospective analysis of a large cohort ( n = 15,055) from the Atherosclerosis Risk in Communities (ARIC) study [ 100 ], dietary renal acid load was positively associated with chronic kidney disease (CKD) incidence (defined by the authors as 25% reduction of estimated glomerular filtration rate (eGFR), CKD related hospitalization, end-stage renal disease, or mortality). This mirrors the findings of a 10-year longitudinal cohort study where the objective was to assess the source of protein intake in a cohort of older women and possible link to incidence for age-related rate of renal function decline. Greater consumption of plant protein was related to slower declines in eGFR, but intake of animal protein was not associated with kidney function decline [ 95 ]. In two one-year intervention studies, patients with stage 3 or 4 CKD were treated with either sodium bicarbonate or fruits and vegetables dosed to reduce renal acid load, a hypothetical metabolic risk factor for kidney damage, by 50% [ 101 , 102 ]. Both treatments ameliorated metabolic acidosis and indices of kidney injury and did so without producing hyperkalemia. In another trial, participants on diets with equivalent nutrient content had lower serum phosphorus and phosphorus excretion when the protein source was vegetarian as compared to animal-based [ 103 ]. The observational outcomes of the Chronic Renal Insufficiency Cohort Study supported these findings to indicate an association between plant protein consumption and reduction in metabolic risk factors for CKD exists [ 104 ]. The totality of this evidence points to the benefit of plant-proteins in the diet to lessen the impact of protein intake in patients with increased protein needs, due to wasting, from glomerular hyperfiltration.

The plant-based proteins from soybean and rice endosperm have demonstrated renal protective properties in diabetic rat models [ 105 ]. One potential mechanism of action for the renoprotective effect of plant protein is an indirect effect mediated by improved glucose homeostasis, with plant protein intake being associated with reduced fatty liver development. Another potential explanation is that a protein such as rice endosperm protein is high in arginine, a precursor of nitric oxide (NO), which is depleted in this rat model [ 105 , 106 ]. The improvement of renal hemodynamics which results from the supplementation of arginine could be the direct result of an increase in NO production [ 106 ]. These plant protein sources bring additional compounds into the mix that need to be considered as well, such as soy isoflavones, which might affect renal function through cell signaling actions and nitric oxide production affecting renal perfusion [ 107 ]. Soy consumption has also been associated with improvements in antioxidant status and systemic inflammation in CKD patients [ 107 ]. Put another way, the whole “protein package” should be considered in terms of health benefits. Soy’s effects on renal function could be the result of the whole food’s impact on risk factors for CKD such as dyslipidemia, hypertension, and hyperglycemia [ 108 ]. In summary, other factors such as fiber and phytochemicals may play a role in renal protection in whole food plant-based diets; however, these components cannot be fully responsible for the renal benefits seen in the studies using protein isolates. In diets high in whole plant foods, it is more likely that the positive effect on renal function is due to synergistic effects from plant-protein and from other plant components. This renoprotective effect is the basis for recommending the incorporation of high-quality plant proteins not only in the diet of those with renal insufficiency [ 109 ], but also the general population.

4.7. Plant Proteins for Lean Body Mass and Strength

Meeting total daily protein needs is important for persons engaging in either strength or endurance training. In addition, the concept of reaching meal total protein and leucine content thresholds of 20–40 and 2–4 g, respectively, several times per day to promote “maximal” muscle protein synthesis (MPS) [ 60 , 110 , 111 , 112 , 113 , 114 ] has become popular among active persons (young and old). Most studies examining the effects of meal protein dose on muscle protein synthesis, especially post-resistance training, fed high-quality animal proteins such as dairy (e.g., whey and casein) or egg protein. Tang et al. [ 115 ] studied the effect of feeding whey hydrolysate, soy protein, and casein, matched to provide 10 g indispensable amino acids, on mixed MPS at rest and over a 3-h period following unilateral leg resistance training. Postexercise, the whey hydrolysate promoted significantly greater MPS than did either soy or casein. However, the soy protein outperformed casein at rest and postexercise. Further, even though it was significantly lower, the postexercise MPS fractional synthetic rate (%/h) for soy protein was still about 80% that of whey. The authors attributed this finding to either differences in the rates of digestion of the three proteins or their leucine content. Because soy protein has a lower percentage of leucine (~8%) compared with whey protein (~12%), it is possible that simply providing a little bit more soy protein to reach the critical leucine threshold is all that is needed to promote comparable levels of postexercise MPS between the two proteins.

Studies with other plant proteins tend to bear this out. In a sample of young women also performing unilateral leg resistance training, increasing protein intake to double the RDA from potato protein elevated both resting and exercise-associated 24-h MPS above the baseline level [ 28 ]. Curiously, in this study, supplementation with an isocaloric carbohydrate placebo also caused comparable increases in MPS in both the resting and postexercise state, so the true benefits of the potato protein were unclear. In another study, ingestion of 35 g micellar casein by older men (non-exercising) versus 35 g wheat protein hydrolysate caused greater increases in MPS in the 4-h postingestion period [ 116 ]. However, upping the dose of wheat protein hydrolysate to 60 g resulted in rates of MPS that exceeded that of 35 g whey protein and were comparable to that of 35 g micellar casein.

Acute measures of MPS occurring a few hours after the ingestion of protein have questionable value in predicting longer-term gains in lean body mass with training [ 117 ]. Gaining muscle mass is a complex process affected by a variety of physiological factors, so actual training studies evaluating the influence of protein supplementation on muscle mass and strength gains over time are needed to better assess the value of plant proteins for muscle building. Some resistance training studies (12–36 weeks) in young adults have reported that fluid milk or whey protein is superior to soy milk or soy protein for muscle mass and strength [ 118 , 119 ]. However, a recent meta-analysis of nine resistance-training studies with a total of 266 participants [ 120 ] was conducted to evaluate the effects of matched protein doses from soy versus animal proteins on muscle mass and strength outcomes. Of the nine studies in the meta-analysis, five compared whey with soy, while four compared soy with other proteins (beef, milk, or dairy protein). Subjects included both young (18–38 years) and older (61–67 years) adults and the duration of training ranged 6–36 weeks (2–5 times per week). Amounts of protein supplemented to the diet ranged 18–85 g/day. There were no differences between soy protein and the animal proteins for improvements in bench press strength, squat/leg press strength, or lean body mass outcomes.

Training studies have also reported positive outcomes for other plant proteins than soy. Joy et al. [ 121 ] reported that 48 g/day of rice or whey protein isolate on training days during an eight-week resistance training program in college-aged adults caused similar improvements in body composition and bench and leg press strength. A study in elite mixed martial artists undergoing six weeks of intense training demonstrated no differences between 75 g/day of whey or rice protein isolate on body composition outcomes [ 122 ]. In addition, pea protein supplementation (25 g twice/day) was shown during 12 weeks of resistance training to increase biceps muscle thickness to the same degree as an equivalent amount of whey protein [ 123 ]. Likewise, Banaszek et al. [ 124 ] supplemented participants in a high-intensity functional training program over eight weeks with 48 g/day of either whey or pea protein and observed that both proteins resulted in similar body composition, muscle thickness, force production, workout performance, and strength. Finally, a meta-analysis of the effects of protein intake on resistance training outcomes concluded that the major considerations for protein intake were to achieve an intake of 1.6 g/kg body weight per day, separating it into 0.25 g/kg doses [ 125 ]. Of minor importance were factors such as timing of intake, postexercise protein dose, and protein source. Part of the explanation for differences in efficacy between plant and animal proteins may have to do with whether short-term (e.g., MPS) compared with long-term (e.g., increases in actual lean body mass) outcomes.

Whey protein is quite effective for promoting increases in both short-term measures of MPS and resistance-training induced gains in lean body mass and strength and, largely due to its high leucine content, can lead to these improvements in lower doses (<30 g/day) [ 119 ] than might be achieved with plant proteins. However, supplementing with larger doses of plant proteins (40 g/day or higher) can provide similar fitness outcomes to those achieved with whey protein. The wider availability of plant-based protein concentrates and isolates now makes it easier to achieve these higher plant protein intakes for those who wish to push the balance of their protein intake more heavily toward plant-based sources.

Another point of importance is the value that might be achieved by combining plant and animal proteins in a supplementation program to take advantage of the relative strengths of each kind of protein. For example, PER determinations in rats with 30:70 animal:plant protein ratios have shown that, for several animal and plant protein combinations, the 30:70 ratio resulted in equivalent or greater PER scores than did the animal protein at 100% [ 126 ]. Similarly, two studies of a protein blend (20 g) containing 25% whey protein isolate, 25% soy protein isolate, and 50% sodium caseinate can promote MPS to a level equivalent to whey protein alone and may be associated with more prolonged positive amino acid net balance (i.e., arteriovenous differences in the leg) compared with whey protein [ 127 , 128 ]. Thus, for those individuals who want to incorporate plant proteins but are still open to animal proteins as well, it is possible to put them together to achieve the desired results.

5. Health Concerns Associated with Plant Proteins

5.1. antinutrients.

One health concern associated with increased dietary intake of plant-based proteins is the presence of antinutrients in plant foods. Antinutrients are natural substances produced by plants that can interfere with the digestion, absorption or utilization of nutrients in food and may have other adverse effects as well [ 129 ]. Antinutrient adverse effects may include leaky gut and autoimmune effects (e.g., lectins and some saponins), protein maldigestion (trypsin and protease inhibitors), carbohydrate maldigestion (alpha-amylase inhibitors), mineral malabsorption (phytates, tannins, and oxalates), interference with thyroid iodine uptake (goitrogens), gut dysfunction, inflammation, and behavioral effects (conversion of cereal gliadins to exorphins) [ 129 ]. Often, the adverse effects of antinutrients have been observed in animals fed unprocessed plant proteins and these observations have triggered fears in people regarding the consumption of some plant foods. However, it is important to note that antinutrients are not always associated with adverse effects and, in some cases, their effects on the body may be positive. At low levels, phytates, lectins, phenolic compounds, enzyme inhibitors, and saponins may help to reduce blood glucose and/or plasma cholesterol and triglycerides [ 129 ]. Saponins may help liver function and reduce platelet agglutination and some saponins, as well as phytates, protease inhibitors, lignans, and phytoestrogens, may reduce cancer risk [ 129 ]. In addition, tannins may have antimicrobial effects [ 129 ]. As such, some of the health benefits of plant-based diets may be attributed to the presence of low levels of these “antinutrients”. Finally, multiple pathways exist for greatly reducing the concentration of antinutrients in plant proteins, including soaking, fermentation, sprouting (germination), heating, gamma irradiation, and genomic technologies [ 129 ]. Food processing techniques make it possible to largely remove antinutrients such as glucosinolates, phytates, erucic acid, and insoluble fiber from canola/rapeseed proteins, which dramatically improves their bioavailability [ 26 ]. Because plant protein concentrates and isolates typically undergo processing to mostly eliminate antinutrients, their digestibility is typically much higher than when the protein remains in the whole food matrix. For example, the protein digestibility of soy protein isolate is 96% or higher, while the protein digestibility of soy flour is only 84% [ 24 , 25 ].

5.2. Soy Protein and Isoflavones

Soy protein has been the target of both health promotion claims and potential adverse health effect concerns for some time due to its content of isoflavones. Isoflavones are compounds that have elements of their chemical structure similar to estrogen and some weakly bind with estrogen receptors [ 130 ]. The concern has been raised that soy isoflavones might have endocrine disrupting impacts on reproductive hormones, largely based on in vitro cell culture or rodent studies involving large doses of isoflavones [ 131 , 132 , 133 ]. The isoflavone content of various soy protein ingredients has been reported as follows (wet basis, expressed as aglycones): defatted and whole soy flours (120–340 mg/100 g), soy protein isolates (88–164 mg/100 g), commercial textured soy proteins (66–183 mg/100 g), and soy hypocotyl flours (542–851 mg/100 g) [ 134 ]. As a result, consumers may choose to avoid soy protein for fear of adverse effects on reproductive or thyroid hormones. However, multiple lines of research over the last 15 years have shown that concerns regarding adverse hormonal effects from physiological amounts of soy foods in the diet are largely unfounded. In 2015, the European Food Safety Authority conducted a comprehensive evaluation of the safety of isoflavone supplements for peri- and postmenopausal women. The evaluation showed that daily doses of 35–150 mg of isoflavones in this population resulted in no increase in breast cancer risk, no effects on endometrial thickness or histopathological changes in the uterus over 30 months (some nonmalignant histopathological changes at 60 months), and no changes in thyroid hormone status [ 135 ].

A meta-analysis of 15 placebo-controlled studies of men of varying ages have reported that soy protein intake up to 60 g/day has not been associated with significant alterations in testosterone, sex hormone-binding globulin, free testosterone, or free androgen index [ 136 ]. Similarly, Dillingham et al. [ 137 ] observed that the feeding of approximately 32 g protein/day for 57 days from either low or high isoflavone soy protein was associated with only minor changes in serum reproductive hormones in young healthy men. In another comparison of low versus high isoflavone soy protein supplementation, the protein supplementation, regardless of isoflavone content, did not influence semen quality parameters (semen volume, sperm concentration, sperm count, sperm mobility, sperm percent motility, total motile sperm count, or sperm morphology) in healthy young men [ 138 ].

Because some types of breast cancer may be estrogen-sensitive, the safety of soy for breast cancer patients has been questioned. The issue of whether soy protein/soy isoflavones affects the risk of breast cancer or its recurrence has also been addressed in multiple investigations and reviews. Messina [ 130 ] concluded that soy foods do not increase the risk of breast cancer and will not worsen cancer outcomes in women with breast cancer. A meta-analysis in 2016 and two more in 2019 reported similar conclusions and further suggested that soy food intake may be associated with a decrease in the risk of breast cancer and improved breast cancer survival [ 139 , 140 , 141 ]. A systematic review of 13 prospective cohort studies for primary breast cancer incidence and five prospective cohort studies examining risk of recurrence and mortality (4–7 years follow-up post first diagnosis) [ 142 , 143 ] stated that soy foods do not affect the risk of primary breast cancer, but, in patients with breast cancer, a diet high in soy is associated with a 25% decrease in cancer recurrence and a 15% decrease in mortality. The protective effect of soy was significant in both estrogen receptor-positive and -negative breast cancer types, but the reduction in recurrence was stronger in the estrogen receptor-negative (HR = 0.64; 95% CI 0.44–0.94) compared with estrogen receptor-positive (HR = 0.81; 95% CI 0.63–1.04) breast cancer type. The American Cancer Society supports the intake of soy foods in breast cancer survivors [ 144 ].

Potential concerns regarding the effects of soy foods on thyroid function may serve as a barrier to increased soy protein intake among consumers. These questions arose based on some cases of goiter in infants on soy infant formula 60 years ago [ 145 , 146 ] and on in vivo [ 147 ] and in vitro [ 148 ] research suggesting that isoflavones inhibit the activity of thyroid peroxidase, a key enzyme that, with iodine, helps the thyroid synthesize the hormones triiodothyronine (T3) and thyroxin (T4).

Despite early concerns regarding potential harmful effects of soy on thyroid function, the weight of current evidence points more strongly to the safety of soy. Recently, Otun et al. [ 149 ] conducted a systematic review and meta-analysis of 18 studies of the effects of soy foods/isoflavones on thyroid hormone function in adults. There were no overall effects of soy or isoflavones on thyroid function, although the authors did note a modest increase in TSH in some studies that was of unclear clinical relevance. Finally, the absence of an epidemiological association between soy food intake and thyroid function in countries where soy intake is high further argues for the safety of soy. While the possibility of adverse effects of soy on thyroid function cannot be ruled out in some sub-populations (e.g., those with marginal iodine status or sub-clinical hypothyroidism), individuals with normal thyroid function and iodine intake should be able to safely consume soy foods/protein [ 150 ].

With regard to hypothyroid individuals on thyroid replacement medication, there is limited case study evidence that soy foods may interfere to some degree with the absorption of levothyroxine in some hypothyroid individuals [ 151 ]. However, even in this situation, the reasonable intake of soy foods may still be acceptable if the dose of levothyroxine is either increased or timed such that it does not coincide with the soy intake [ 150 , 151 ].

5.3. Plant-Based Protein and Allergenicity

As mentioned above, the trend towards an increase in plant protein consumption stems from available evidence indicating that the source of protein (or, the protein “package”), not just the amount of protein, influences our health. Healthcare professionals are recommending adding different protein sources like soy, beans, nuts, or other plant-based proteins in place of red meat and processed meats to lower the risk of several diseases [ 152 ]. As the health food industry has grown, a focus for food manufacturers is the trend towards incorporating more plant-based foods to appeal to consumers. This is a trend not only in adults but also in the pediatric population. Increasingly, parents and caretakers are feeding infants and young children plant-based “milk” alternatives to cow milk [ 153 , 154 , 155 , 156 , 157 ] as well as providing more vegetarian options such as plant-based nuggets and burgers into their children’s daily meal plan. Such dietary choices may have unintended outcomes.

One of these outcomes is allergenicity. A food allergy is an adverse health effect resulting from a specific immune response that occurs reproducibly on exposure to a given food [ 158 ]. The health effect, called an allergic reaction, occurs because the immune system attacks food proteins that are normally harmless. Symptoms range from mild and transient to severe and life-threatening. According to Food Allergy Research and Education, 32 million Americans are living with potentially life-threatening food allergies. Based on a review of the literature, food allergy is estimated to affect more than 1–2% and less than 10% of the population [ 159 ].

In the U.S., more than 170 foods have been identified as triggers of food allergy [ 158 ]. The most common foods causing most of the significant allergic reactions include peanuts, tree nuts, fish, shellfish, milk, egg, wheat, and soy [ 158 ]. The most common food allergies in children and adults in the United States are allergies to peanut, milk, shellfish, and tree nut, with milk being most prevalent in children and shellfish most prevalent in adults [ 160 , 161 ]. Common food allergens from other countries include: sesame seeds in Canada, European Union (EU), Australia/New Zealand; mustard in EU and Canada; Buckwheat in Japan and Korea; and lupines in the EU [ 162 ]. The above have become common food allergens since they are frequently consumed, consumed in relatively large amounts, and consumed in early life stages. As plant protein consumption increases, so will the percentage of allergenic responses for these very reasons.

Take, for example, lupines. The Lupinus genus is closely related to other legumes, such as peanuts, soy, chickpeas, peas, lentils, and beans [ 163 ]. In the EU, lupine flour and other lupine protein ingredients were introduced in the 1990s as replacements for soy and wheat [ 164 ]. Since its introduction, allergic cross-reactions were noted in some peanut-allergic individuals. This was also observed in Australia, and now lupine is listed on the priority allergen lists by the International Union of Immunological Societies Allergen Nomenclature Subcommittee in the EU and Australia [ 164 ].

This is a very similar story to soy protein. Soy originated in southeast Asia and was first domesticated in China around 1100 BC, not being introduced in the U.S. until the 1760s [ 165 ]. Tofu and soy sauce were some of the first soy foods for humans. In 1930, soy infant formula was developed, but it was not widely used until the 1950s. In 1959, soy protein isolates were first introduced. From the 1950s, when some milk allergic infants transitioning to soy formula subsequently developed soy allergy, to the 1960s when higher intakes of soy protein in multiple different food sources became possible, the prevalence of soy allergies increased. Even so, soy has demonstrated value as a quality source of plant-based protein. Studies in children have demonstrated that soy supports normal growth and development [ 166 ] and improves growth when substituted for other legumes in malnourished children [ 167 , 168 ]. Overall, a wealth of evidence exists to demonstrate soy’s value as part of a healthy and varied diet [ 169 ]. All food proteins have the potential to cause allergic reactions, and children tend to be more sensitive to dietary proteins than adults [ 170 ]. While soy is a potential allergen in children, soy allergy in children is far less common than allergies to dairy [ 171 ], and soy allergy has a prevalence of only 0.4% among American children [ 172 , 173 ] and 0.32% in Canadian children [ 174 ]. This compares with prevalence rates of 2.0–3.0% for milk allergy [ 173 , 175 ], 2.0% for peanuts [ 173 ], 0.8–2.0% for eggs [ 176 , 177 ], and 1.0% for tree nuts [ 173 , 178 , 179 ]. Children also tend to outgrow soy allergies over time. One study reported that ~70% of infants with a soy allergy outgrew the allergy by the age of two years [ 180 ], and evidence suggests that, by the age of 10 years, only about 1 in 1000 children continue to have a soy allergy [ 178 ].

The chemical analysis of plant proteins has been happening for centuries, with the isolation of gluten proteins from wheat dating back over 250 years ago [ 181 ]. More recently, increasing emphasis has been placed on the role of plant proteins as allergens, particularly in Europe and the U.S.A., and in relation to novel and transgenic foods [ 181 ]. Plant-based food allergens fall into four main families: the prolamin superfamily, cupin superfamily, Bet v 1 family, and profilins. Over 50% of the plant protein allergens fall into two categories, the prolamin and cupin superfamilies [ 181 ]. The prolamin family is characterized based on the presence of a conserved eight cysteine amino acid residue pattern CXnCXnCCXnCXCXnCXnC. This stabilizes the protein structure which contributes to overall allergenicity of proteins in this class (highly resistant to heating, proteolysis, and digestion). The major allergens include cereal prolamins, 2S albumins, non-specific lipid transfer proteins, and α-amylase and trypsin inhibitor protein families [ 182 , 183 , 184 , 185 , 186 ].

The prolamin family are seed proteins which include but are not limited to wheat, barley, rye, soybean, rice, maize, and sunflower. Consequently, the prolamin superfamily currently forms the largest and most widely distributed group of plant food allergens [ 181 ]. One can visit the Food Allergy Research Resource Program (FARRP) database ( http://www.allergenonline.com/ ) to learn about more different types of allergens. FARRP database contains a comprehensive list of 2171 protein (amino acid) sequence entries that are categorized into 873 taxonomic-protein groups of unique proven or putative allergens (food, airway, venom/salivary, and contact) from 423 species [ 187 ].

All protein sources have the potential to have an allergenic effect. As novel plant-based sources of protein emerge into the market, they will inevitably elicit an allergenic response in someone. An example of this is pea protein. Peas are part of the legume family which also includes peanuts, beans, lentils, and soybeans. Due to other plant proteins, such as soy and wheat, having documented allergenic responses, pea protein has been viewed as a potentially less allergenic alternative. Pea protein use as a human food commodity has been steadily increasing in the U.S. Pea protein’s availability, physical and processing characteristics, nutritional value, and low cost have increased its use as a novel and effective alternative to substitute for soybean or animal proteins in functional foods [ 188 ]. It can be found in protein powders, medical formulas, and a variety of food substances such as milk, yogurt, cheese, and baked goods. While not common, there have been case studies documented of those with a proven peanut allergy having a reaction to pea protein [ 189 , 190 ]. What is interesting is that plain cooked yellow peas (e.g., entry of peas, split, mature seeds, cooked, boiled, and without salt) average approximately 8% protein by weight [ 37 ]. In comparison, current products include pea protein isolates (70–95% protein), concentrates (60–70% protein), and hydrolysates (90–95% protein) [ 189 ]. The products listed above provide much higher protein loads than someone eating a serving of cooked peas. It is not surprising, then, that someone not allergic to a serving of whole peas might experience an allergenic response to the much larger doses of pea protein found in products containing pea concentrates and isolates. Although some believe that pea and soy protein have a similar allergenic prevalence [ 191 ], pea protein allergenicity has not been extensively studied. While pea proteins are not required to be identified as a potential allergen on food labels in the U.S. or Canada, some have taken notice of pea as a “hidden allergen” [ 192 ].

While all dietary proteins are foreign proteins to the human immune system, only a few proteins from plant and animal origin cause an IgE-mediated immune response, typically in a small number of people [ 162 ]. Plant protein categories include legumes, nuts and seeds, whole grains, and other (mainly fruits and vegetables). At the time this article was written, there are insufficient data on all plant proteins, as some are novel and allergenic responses are just starting to emerge. This does not mean new protein sources should not be explored, but that labeling should be clear so those who do develop an allergy know what is in them.

6. Conclusions

Products made with plant-based protein and plant-based whole food diets are growing in popularity. Plant protein has been associated with benefits regarding health and physical function. The trend toward increasing plant protein intake is likely to continue as consumers expand their knowledge of the nutritional benefits of protein and sustainability concerns about the food supply are raised. Plant proteins may also become more valuable if current public health protein recommendations are revised upward. However, plant proteins differ in nutritional quality and those who choose to largely emphasize plant versus animal proteins need to be aware of these differences when planning an appropriate diet, especially in more vulnerable populations. In addition, potential safety issues have come to light and may continue to emerge with the increased amount, variety, and forms of plant proteins that are incorporated into the diet. More research is needed on the best ways to incorporate plant proteins into the diet safely and effectively.

Author Contributions

All authors were involved in the design, preparation, and review of this manuscript and the decision to publish. J.C.L.-B. wrote Section 4.1 , Section 4.2 , Section 4.3 , Section 4.4 and Section 4.5 , M.W. wrote Section 4.6 , C.A. wrote Section 5.3 , and S.R.H. wrote the remainder. All authors have read and agreed to the published version of the manuscript.

This research received no external funding and was supported by Abbott Nutrition.

Conflicts of Interest

The authors are employed by Abbott Nutrition.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Nutrition in Plants Important Questions Class 7 Science Chapter 1

Nutrition in Plants Class 7 Science Chapter 1 Important Questions and Answers are provided here. We prepared these extra questions based on the latest NCERT Class 7 Science Book. These important questions will help you to properly understand a particular concept of the chapter. Practicing class 7 important questions before the exam will help you to get excellent marks in the exam. 

Class 7 Science Chapter 1 Nutrition in Plants Important Questions

Very short answer type question.

1: Name some components of food. Answer:  Carbohydrates, proteins, fats, vitamins and minerals.

2: Define nutrients. Answer: Carbohydrates, proteins, fats, vitamins and minerals are essential components of food, these components are called nutrients.

3: Give an example of autotrophs. Answer:  All green plants.

4: Give an example of heterotrophs. Answer:  Animals and human beings.

5: Plants prepare their food by using raw materials present in ___________. Answer:  Surrounding

6: What do you mean by nutrition? Answer:  Nutrition is the mode of taking food by an organism and its utilisation by body.

7: Name the food factories of plants. Answer:  Leaves

8: Name the tiny pores present on the surface of leaves. Answer:  Stomata

9: Name the green pigment present in leaves. Answer:  Chlorophyll

10: ____________ helps leaves to capture the energy of sunlight Answer:  Chlorophyll

11: Why photosynthesis is named so? Answer:  Because the synthesis of food occurs in presence of sunlight.

12: Sun is the ultimate source of energy for all living organisms. True / False Answer:  True

13: Where does the nucleus of cell lies? Answer:  In the centre of cell.

14: State the equation for the process of photosynthesis. Answer:  Carbon dioxide + water → carbohydrate + Oxygen

15: The nucleus in a cell is surrounded by a jelly like substance called ___________. Answer:  Cytoplasm

16: Why algae present in stagnant water bodies are green in colour? Answer:  Because they contain green colour pigment chlorophyll.

17: Name a component of food other than carbohydrate synthesize by plants. Answer:  Proteins and fats

18: Name some insectivorous plants. Answer:  Pitcher plants and Venus flytraps are insectivorous plants.

19: During photosynthesis plants take in ____________ and releases ____________. Answer:  Carbon dioxide, oxygen

20: Some organisms live together and share shelter and nutrients, this type of relationship is called Answer:  Symbiotic relationship.

21: Lichen is a symbiotic association between __________ and fungi. Answer:  algae

22: Name the edible fungi. Answer:  Mushroom.

23: Name the organism responsible for converting atmospheric nitrogen into soluble forms. Answer:  Rhizobium bacteria.

24: Give an example of parasites. Answer:  Cuscuta plants.

25: Give an example of saprotrophs.

Answer:   Fungi

26: Carbon dioxide is released during photosynthesis. True/ False. Answer:  False

27: During photosynthesis solar energy is converted into chemical energy. True/ False. Answer:  True

28: Name a plant that has both autotrophic and heterotrophic mode of nutrition. Answer:  Insectivorous plants

29: Name a parasitic plant with yellow, slender and tubular type of stem. Answer:  Amarbel

30: Name the pores present in leaves through which exchange of gas takes place. Answer:  Stomata

31: Animals are autotrophs. True/ False. Answer:  False

Short Answer Type Questions

1. What is Nutrients?

Answer:   Carbohydrates, proteins, fats, vitamins and minerals are components of food. The chemical substance present in components of food is necessary for our body and is called nutrients.

2. How humans and animals are directly or indirectly dependent on plants.

Answer:  All living organisms require food. Plants can make their food themselves but animals including humans cannot. They get it from plants or animals that eat plants. Thus, humans and animals are directly or indirectly dependent on plants.

3. What is food?

Answer:   Food is the source of energy and every cell of an organism gets energy by the breakdown of glucose. The cells use this energy to carry out vital activities of life.

4. Why do we need food?

Answer:   Living organisms need food to build their bodies, to grow, to repair damaged parts of their bodies and provide the energy to carry out life processes.

5. How do plants obtain the raw materials from the surroundings?

Answer:   Water and minerals present in the soil are absorbed by the roots and transported to the leaves.

Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. Such pores are called stomata. These pores are surrounded by ‘guard cells’.

6. What is cell?

Answer:  The bodies of living organisms are made of tiny units called cells therefore Cell are called the building blocks of living organism. Cells can be seen only under the microscope. Some organisms are made of only one cell. They are called Unicellular Ex. Amoeba, Paramecium etc. Living organism made up of many cells are called Multi cellular like man, tree etc.

7. What is the cell membrane?

Answer:   The cell is enclosed by a thin outer boundary, called the cell membrane Most cells have a distinct, centrally located spherical structure called the nucleus The nucleus is surrounded by a jelly-like substance called cytoplasm.

8. What is tissue?

Answer:  A tissue is a group of cells that perform specialized function in an organism. For example, the vascular tissue for the transport of water and nutrients in the plant is called the xylem.

9. What are the main requirements of photo synthesis?

Answer:  Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of Photosynthesis.

10. Explain the process of Photosynthesis?

Answer:   Carbon dioxide from air is taken in through stomata. chlorophyll helps leaves to capture the energy of the sunlight. This energy is used to synthesize (prepare) food from carbon dioxide and water. Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis.

11. Why sun is called the ultimate source of energy for all living organisms?

Answer:  The solar energy is captured by the leaves and stored in the plant in the form of food. and this in turn use by other organism to get food to obtain energy Thus, sun is the ultimate source of energy for all living organisms.

12. Why algae are green in colour?

Answer:  Algae contain chlorophyll which gives them the green colour. It can also prepare their own food by photosynthesis.

13. What are the main components presents in carbohydrates?

Answer:  The main components present in carbohydrates are carbon, hydrogen and oxygen.

14: Differentiate between nutrients and nutrition.

Answer:   Carbohydrates, proteins, fats, vitamins and minerals are essential components of food, these components are called nutrients, but Nutrition is the mode of taking food by an organism and its utilisation by the body.

15: Differentiate between autotrophs and heterotrophs.

Answer:   Green plants are called autotrophs as they prepare their own food from simple substances, but animals and most other organisms are called heterotrophs as they take in ready-made food prepared by the plants.

16: Explain the food factory of plants.

Answer:   Leaves are called food factory of plants, as the synthesis of food takes place in leaves of plants. Water and minerals present in soil are absorbed by roots and transported to leaves via stem. Carbon dioxide from air is taken in through tiny pores on surface of leaves called stomata.

17: How water and minerals are transported to leaves from roots?

Answer:   There are vessels inside a plant which run like pipes throughout the root, stem branches and leaves, by going through these vessels water and minerals are transported to leaves from roots.

18: Draw a labelled diagram of cell showing nucleus and cytoplasm. Answer: 

19: Define chlorophyll.

Answer:   Chlorophyll is the green colour pigment which helps leaves to capture energy from sunlight to carry out the food making process of plants by the leaves.

20: Explain the role of chlorophyll in the process of photosynthesis.

Answer:   Chlorophyll is the green colour pigment which helps leaves to capture energy from sunlight to carry out the food making process of plants by the leaves. It is the green photosynthesis pigment which provides energy necessary for photosynthesis.

21: Define photosynthesis along with the equation for the same.

Answer:   Photosynthesis is the food manufacturing process of green plants containing chlorophyll, in presence of sunlight, with the help of carbon dioxide and water to synthesise carbohydrates. The equation for the process is as follow: Carbon dioxide + water —> carbohydrate + Oxygen

22: What is the function of stomata in leaf of a plant?

Answer:   Stomata are the tiny pores present on the surface of leaves which helps in exchange of gases, the pores in stomata are surrounded by guard cells.

23: Why do we need food?

Answer:   Living organisms need food to build their bodies, to grow, to repair damaged parts of their bodies and provide with energy to carry out life processes.

24: Draw a labelled diagram showing the process of photosynthesis. Answer: 

25: Draw diagram of a leaf showing chlorophyll, and stomata in it. Answer: 

26: What is the cell membrane?

Answer:   The cell is enclosed by a thin outer boundary, called the cell membrane Many cells have a distinct, centrally located spherical structure called the nucleus. The nucleus is surrounded by a jelly-like substance called cytoplasm.

27: What are the main requirements of photosynthesis?

Answer:   Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of Photosynthesis.

28: Why colours of algae are green?

Answer:   Algae contain chlorophyll which gives them green colour and because of chlorophyll it can also prepare their own food by photosynthesis.

29: What are the main components presents in carbohydrates?

Answer:   The main components presents in carbohydrates are carbon, hydrogen and oxygen.

30: From where do the plants obtain nitrogen?

Answer:   Soil has certain bacteria that convert gaseous nitrogen into a usable form and release it into the soil. These soluble forms are absorbed by the plants along with water. By adding fertilizers rich in nitrogen to the soil farmers also made nitrogen available for plants.

31: Define insectivorous plants along with examples.

Answer:   There are few plants which can trap insects and digest them. Such plants may be green or of some other colour. Such insect-eating plants are called insectivorous plants. Example: Venus Flytrap and Pitcher plant.

32: Explain how Pitcher plants get their nutrition?

Answer:   When an insect lands in the pitcher, the lid closes and the trapped insect gets entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher.

Long Answer Type Questions

1: Sun is called the ultimate source of energy for all living organisms. Comments.

Answer:   The solar energy is very important to carry out the process of photosynthesis, it is captured by the leaves and stored in the plant in the form of food. And this in turn use by other organism to get food to obtain energy Thus, we say that sun is the ultimate source of energy for all living organisms.

2. What is Symbiosis? What is Symbiotic relationship?

Answer: Symbiosis:  It is the type of nutrition in which two different kinds of depend on each other for their nutrition. In this both the organisms are benefited by each other Example: Lichen. In this one alga and one fungus live together and remain in symbiotic relationship.

Symbiotic Relationship:  Some organisms live together and share shelter and nutrients. This type of relationship is called symbiotic relationship.

3: Explain the two mode of nutrition in plants.

Answer:   

Autotrophs or Autotrophic : – In this mode of nutrition organisms make their food themselves from simple substances. All green plants are Autotrophs (Auto means self and trophs means nourishment)

Heterotrophs or heterotrophic : – Heterotrophic organisms are those who obtain food from other organisms. Since these organisms depend on other organisms for their food, they are called consumers. All animals and non-green plants like fungi come under this category.

4. What are stomata? Explain their function.

Answer:  Stomata are tiny pores on the underside of the leaf surface that are surrounded by guard cells. Their functions are to exchange gases by diffusion for photosynthesis and respiration and to cause transpiration by evaporation of water from the leaf surface.

5. How is sunlight used by the plant for photosynthesis?

Answer:  Sunlight is the energy source for photosynthesis. It is trapped by the green pigment chlorophyll that is present in the leaves and all green parts pf the plants. The chlorophyll is present in organelles called chloroplasts. Most of the chlorophyll is present in the leaves and therefore leaves are the major site for trapping sunlight to convert it to chemical energy.

6. Explain how photosynthesis occurs in plants.

Answer:  Photosynthesis is the process by which solar energy is converted to chemical energy by the green plants. In this process simple inorganic molecules like carbon dioxide and water are used to synthesise organic food like starch. The reaction requires energy from sunlight. Sunlight is trapped by the pigment chlorophyll present in the leaves. The raw materials for photosynthesis are carbon dioxide and water. Carbon dioxide is absorbed from the atmosphere whereas water is absorbed from the soil. The energy from sunlight converts carbon dioxide and water to starch and oxygen. Starch is used as food by plants and other animals whereas the oxygen is released into the atmosphere. The overall reaction of photosynthesis can be represented as follows:

7. How do plants obtain nutrients other than carbohydrates?

Answer:  Plants synthesise carbohydrates using energy from sunlight to convert carbon dioxide and water to starch. The other nutrients are however obtained directly from soil. Nitrogen is absorbed as soluble nitrogen compounds from the soil. The nitrogen compounds are present in the soil due to the action of nitrogen fixing bacteria like Rhizobium that live in symbiotic association with roots of leguminous plants. Nitrogen compounds can be replenished by the addition of fertilizers and manure to the soil. Some plants like the pitcher plant and Venus flytrap fulfill their nitrogen requirements by insectivory. In this case the insects are trapped and digested by plant parts and the nutrients are released into the plant body.

8. What is the mode of nutrition in fungi?

Answer:  The mode of nutrition in fungi is heterotrophic. They cannot synthesize their own food and are dependent on other ‘organisms’ for their carbon source. They perform extracellular digestion by releasing enzymes into their environment and obtain organic and inorganic nutrients through absorption.   There are three main ways of obtaining nutrition:   (i) Saprotrophic:  Decomposition of ‘dead organic matter’.   (ii) Parasitic:  Feeding from a living host. (iii) Mutualism:  Living in a mutually beneficial interaction with another organism. Example:  lichen is a mutualism between fungi and algae). 

9. How can we demonstrate that chlorophyll is necessary for photosynthesis?

Answer:  Importance of chlorophyll can be demonstrated by using a variegated leaf. The outline of the leaf is traced on a paper and the green areas are marked before the start of the experiment. The leaf is placed in sunlight for few hours to allow photosynthesis. The leaf is then decolourized by boiling in alcohol. To this iodine solution is added. It can be observed that the green areas of the leaf turn blue-black in response to iodine solution indicating the presence of starch. Thus it can be seen that photosynthesis occurs in the green areas of the variegated leaf showing that chlorophyll is important for photosynthesis.

10: Why do organisms need to take food?

Answer:  Food is required by all living organisms mainly for four reasons or purposes:

• Food helps a living organism to grow. If enough food is not given or if, the food given is not of right kind, the organism will not have proper growth.
• Another important function of food is to provide energy which is required for any living organism for movements and other activities.
• Food is also needed by living organisms for replacement and repairing of their damaged parts.
• Food provide us the power to fight against infections and diseases.

11: Distinguish between a parasite and a saprotroph. Answer:

12:   Give a brief description of the process of synthesis of food in green plants.

Answer:  Leaves have a green pigment called chlorophyll. In presence of sunlight, they use carbon dioxide and water to synthesize carbohydrate. During this process oxygen is released. The carbohydrates ultimately get converted into starch. Carbon dioxide from air is taken through stomata. Water and minerals are absorbed by roots and transported to leaves.

13. Whether food is made in all parts of a plant or only in certain parts?

Answer:  Only certain part plant like leaves having green pigment chlorophyll. So Leaves are called the food factories of plants.

Besides leaves, photosynthesis also takes place in other green parts of the plant — in green stems and green branches. The desert plants have scale- or spine-like leaves to reduce loss of water by transpiration. These plants have green stems which carry out photosynthesis.

14. How do the raw materials transport them to the food factories of the plants?

Answer:  Plants have pipe-like vessels to transport water and nutrients from the soil. The vessels are made of special cells, forming the vascular tissue. The vascular tissue for the transport of water and nutrients in the plant is called the xylem. The vascular tissue for the transport of water and nutrients in the plant is called the xylem. Thus, xylem and phloem transport substances in plants.

15. Why are leaves called the food factories of plants? Explain.

Answer:   Leaves are called the food factories of plants due to following functions: 1. Green leaves have all the raw materials necessary to carry the process of photosynthesis. 2. They have chlorophyll (green pigment) which captures the energy of sunlight. 3. Leaves consist of tiny pores called stomata on their surface. 4. Carbon dioxide from air is taken in through stomata.  5. Water and minerals are absorbed by the roots from the soil and transported to the leaves by vessels.

16: How would you test the presence of starch in leaves?

Answer:   Take a potted plant which has been exposed to sunlight and pluck a leave from the plant. Then boil it in water for 5 min to soften it and then place the leave in a test tube containing alcohol ,place the test tube in a beaker containing water gently heat the beaker till the alcohol dissolves in the chlorophyll and the leaves loses its green colour. Now wash the leaf with water and then place it on a plate and add a few drops of iodine solution the parts that turn blue black show the

17: How humans and animals are directly or indirectly dependent on plants?

Answer:   All living organisms require food. Plants can make their food themselves by organic substances but animals including humans cannot make their food themselves. They get it from plants or animals that eat plants. Thus, humans and animals are directly or indirectly dependent on plants.

18: Whether food is made in all parts of a plant or only in certain parts? Explain.

Answer:   Only certain parts of plant like leaves have green pigment called chlorophyll. So Leaves are called the food factories of plants. Besides leaves, photosynthesis also takes place in other green parts of the plant like in green stems and green branches. The desert plants have scale or spine like leaves to reduce loss of water by transpiration. These plants have green stems which carry out the process of photosynthesis.

19: What is cell?

Answer:   The body of living organisms are made of tiny units called cells, therefore Cell are called the building blocks of living organism. Cells can be seen only under the microscope. Some organisms are made of single cell they are called Unicellular. Ex. Amoeba, Paramecium etc. While others are made of multicells and are called multicellular. Ex. man, tree etc.

20: What is saprotrophic mode of nutrition?

Answer:   This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition. Plants which use saprotrophic mode of nutrition are called saprotrophs. Example Fungi that secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it.

21: What do you understand by symbiotic relationship present in some organism?

Answer:   Some organisms live together and share shelter and nutrients. This is called symbiotic relationship. E.g. an alga, and a fungus live together fungus provides shelter, water and minerals to the alga and, in return, the alga provides food which it prepares by photosynthesis. In this kind of association both partners are benefited.

22: How nutrients are replenished in soil?

Answer:   Nutrients are replenished in soil by following ways:

• By spreading manure or fertilizers that contain nutrients such as nitrogen in the fields
• By the bacterium Rhizobium that is commonly present in rot nodules of leguminous plant that can take atmospheric nitrogen and convert it into a soluble form like nitrates.

23: What do you mean by Symbiosis?

Answer:   Symbiosis is the type of nutrition in which two different kinds of organisms depend on each other for their nutrition. In this both the organisms are benefited by each other e.g., lichen is a symbiotic association between algae and fungi. In this one alga and one fungus live together and remain in symbiotic relationship.

24: What is the role of leguminous plants in replenishing soil fertility?

Answer:   Rhizobium is a type of bacteria that cannot make its own food and lives in the roots of gram, peas, moong beans and other legumes, it converts atmospheric nitrogen into usable form which increases the fertility of soil, and legumes provide food and shelter to the bacteria.

25: What do you mean by parasitic nutrition?

Answer:   The mode of by which parasitic organism get and synthesize their food is called parasitic nutrition. Example Cuscuta. It does not have chlorophyll; it takes readymade food from the plant on which it is climbing. The plant on which it climbs is called a host. In a parasitic nutrition only one of the partners is benefited and other is not.

50 Ways to Add 100+ Plants to Your Diet

And why the future of your health depends on variety.

Our product picks are editor-tested, expert-approved. We may earn a commission through links on our site. Why Trust Us?

It’s hard to know exactly, Daniel McDonald, Ph.D. , a UC researcher, told me recently. One possibility is that, because microbes like to feast on plant fiber , the greater variety is simply healthier for them. Or it could be that certain microbes subsist primarily on certain types of plant fibers, so when we limit the categories of plants we eat, we hinder some aspects of our microbiome and wind up throwing the whole party into chaos.

There’s a second reason why a diverse diet is so much healthier, which has to do with phytochemicals—the unique nutrients found in plants. Each plant has its own set, and there are at least 25,000 different plant-based nutrients that we know of. (That’s a lot more than you’ll find in even the most comprehensive multivitamin !)

The Full-Body Fat Fix

Each one of these thousands of nutrients plays a unique role in maintaining overall health: Some have been linked to slowing cognitive decline ; others regulate immune system function ; still others reduce blood pressure and arterial plaque.

But these diverse nutrients don’t work alone. They all work as part of a system, like an orchestra, to create a powerful anti-inflammatory effect. So, if your diet is limited to a routine of potatoes , apples, and broccoli, you’re not really feeding your body, or your microbiome, all of the nutrients it needs.

But there’s an unlimited array of ideas for maxing out your plant intake—without having to heat a skillet or pick up a menu.

Here are 50 favorites.

1. Amp up your loaf. Try a super-packed multigrain bread like Dave’s Killer Bread, which comes loaded with twenty-one different whole grains and seeds including whole wheat, flax, sunflower seeds, sesame seeds, pumpkin seeds, oats, barley, and more.

2. Sneak ground flaxseed into pancake or waffle batter. No one will know!

3. Or steam and purée some cauliflower, and sneak it into pancakes, muffins, even mac and cheese. Again, no one will know!

4. Up your pancake game even more by using buckwheat, a high-fiber, high-protein, gluten-free alternative.

5. Give every smoothie a minimum of six unique plants.

6. If you’re a cereal lover, make a game of topping it with a different fruit, nut, and seed each morning of the week. Strawberries, almonds, and pumpkin seeds today; raspberries, walnuts, and sunflower seeds tomorrow.

7. Speaking of nuts, next time you’re hosting a cocktail party, get the nut mix with lots of different nuts, instead of those tired old peanuts.

8. Wait . . . did someone say cocktails? Let’s take something sinful and make it soulful: Muddle some mint for a mojito; use fresh ginger in rum drinks; float some juniper berries in gin. (Just make sure you eat the herbs—no second drink until all the plants are gone.)

9. And if celery garnishes your Bloody Mary, make sure you eat that, too.

10. Wrap your sandwich in cauliflower wraps instead of those sad flour tortillas.

11. Speaking of which, when at a Mexican restaurant, always ask for corn tortillas, which are made from whole grain, instead of flour tortillas, which are just white flour and lard.

12. Never eat ice cream naked. Always top it with nuts and berries (most Froyo joints have plenty of options).

13. And never order a pizza without at least one vegetable topping. Try something new: artichokes, fresh garlic, spinach, broccoli.

14. Check out the new “rice” options, including broccoli, cauliflower, and hearts of palm.

15. Or, instead of plain old white or brown rice , cook up a wild rice blend, which can contain four or five different plants.

16. Play around with new pasta options, including dried pastas made from lentil, chickpea, or brown rice.

17. Or forget about dried pastas altogether and check out alternatives like spaghetti squash or zucchini spirals.

18. Speaking of pastas, you can find frozen raviolis stuffed with spinach, mushroom, eggplant, and squash. Why limit your meal to just one?

19. Check the freezer section for unusual smoothie ingredients—jackfruit, acai, coconut, aloe vera, dragon fruit.

20. Swap that milk chocolate out for a dark chocolate bar that’s 72 percent cacao or better.

21 . Speaking of chocolate, cacao nibs are broken pieces of cocoa bean that make for fun dessert toppings or even additions to your morning cereal, along with berries and nuts.

22. Find new flours for baking, such as almond, cassava, coconut, chickpea, oat, teff, sorghum, millet, hazelnut, and cauliflower.

23. Up your dipping game with sweet potato chips, plantain chips, or taro chips.\

24. And if you’re dipping chips, make your own salsa fresca with chopped tomatoes, parsley, onion, seeded jalapeño, and lime juice. Or swap in guacamole or hummus for boring onion dip.

25. Snack on dried seaweed (yes, kids love it, too).

26. Look for alternative crackers like Mary’s Gone Crackers, which are made of brown rice, quinoa, pumpkin seeds, sunflower seeds, poppy seeds, and flaxseed.

27. Or forget the crackers altogether and try munching on mushroom crisps or cauliflower crisps.

28. Try Banza mac and cheese—it’s mac and cheese made with chickpeas.

29. Look for soup mixes with a wide array of beans and lentils instead of just the same old black bean soup.

30. Pile fresh herbs on top of any fish or chicken you roast in the oven. A little olive oil and salt is all you need to turn it into a flavor explosion.

31. Pour hemp seeds into any smoothie or breakfast cereal. They’re loaded with protein, fiber, and healthy fats.

32. Include one piece of fruit every time you have a snack. Craving some cheese? Pair it with an apple. Want chocolate? Cherries or strawberries will go well with that.

33. Give Granny a break. Sure, everyone loves the firm texture and crisp flavor of Granny Smith apples, but there are dozens of varieties to experiment with, and each one is its own plant. Play around with Gala, McIntosh, Fuji, Cortland, GoldenDelicious, Pink Lady, and all the other varieties on offer.

34. Same goes for tomatoes—try cherry, beefsteak, plum.

35. Or pears (Bartlett, Bosc, D’Anjou).

36. Look for spring or mesclun mixes in the supermarket, and consider picking up some unexpected salad greens like water- cress, sprouts, frisée, and chicory.

37. Move beyond peanut butter and keep almond butter, sunflower butter, and cashew butter on hand as well.

38. Skip the jellies and pick up some of those fancy jams at the farmers market. They’re made with whole fruit—you can see the seeds inside—and that counts.

39. Or go one better and use whole berries with your peanut butter and whole-grain bread. Raspberries and blackberries are especially delicious.

40. When it comes to berries, go wild. Wild blueberries are a dramatically different plant from those raised on farms, and you can find them in the freezer section. Or check out the briar patches in your neighborhood and see if you can track down some wild raspberries or blackberries in summertime.

41. Try unusual nuts like macadamia or Brazil nuts.

42. Use dates to add sweetness. Blended into smoothies or chopped into brownies or muffins, they’re a whole-plant alternative to honey or sugar.

43. Skewer your expectations. Instead of plain old steak or chicken, use cubes of meat on skewers with mushrooms, zucchini, tomatoes, even pineapple. (Tip: Soak wooden skewers in water before putting them on the grill to keep them from burning up prematurely.)

44. Make the salad bar your friend. See how many different colors you can fit on one plate. Don’t sleep on the beets, radishes, and green beans.

45. Play around with different types of citrus. Instead of just navel oranges, try mandarins, blood oranges, kumquat, tangelo, pomelo—there’s a whole world of flavors out there.

46. Pie before cake. Pumpkin, blueberry, apple, peach, cherry . . . anything with a whole fruit in it is a better choice than plain old white flour.

47. Stock your fridge with chia seed pudding. Add chia seeds, a nondairy milk like oat or soy, and a touch of honey. Stir, let sit for ten minutes, then stir again and refrigerate. Serve with chopped fruits on top. It’s a breakfast; it’s a snack; it’s a dessert!

48. When in doubt, get the chili. From Waffle House to Wendy’s, plenty of restaurants that seem far from healthy offer plant-rich chilies.

49. Spice up your salad with flowers. Violets and nasturtium are two common edible flowers that seem to grow anywhere. Pick them, let them sit for a few hours on the counter to release any bugs hidden within, and add to your salad or decorate your plate as a garnish. And then . . .

50. Eat the garnish. Whether it’s a sprig of mint on a scoop of ice cream, an orange slice on a tequila sunrise, or a frond of parsley on a plate of pork chops, most of us ignore these modest plant offerings—and pass up an opportunity to feed our microbiome what it craves.

This article is an excerpt from The Full-Body Fat Fix : The Science-Based 7-Day Plan to Cool Inflammation, Heal Your Gut, and Build a Healthier, Leaner You!

.css-1fpt53b{height:1.25rem;}@media(max-width: 48rem){.css-1fpt53b{overflow:unset;line-height:1.25rem;}}@media(min-width: 48rem){.css-1fpt53b{line-height:1.25rem;}}.css-1fpt53b:before{background-color:#D2232E;color:#fff;margin-right:0.625rem;width:1.25rem;height:1.25rem;content:'';display:block;} Nutrition

Try Guy Fieri's Fennel & Citrus Salad

Guy Fieri Is—Holy Moly Stromboli—Fit!

Dietitians Recommend These Magnesium Supplements

Shop the Best Melatonin for Sleep

Do Multivitamins Even Do Anything?

The Best Time of Day to Take Creatine

What You Should Know About Probiotic Side Effects

The Truth About Those Viral HMB Supplements

Experts Recommend This L-Glutamine Supplement

Should You Be Taking a Fiber Supplement?

Everything You Need to Know About Omega-5s

Plant-based meats are good for the planet—but what about your health?

When you go out for a burger , you face a lot of choices: Fries or onion rings, bun or lettuce wrap, beef patty or veggie burger? Veggie, of course! That’s the healthier choice, right? 

Not so fast.

Because while there’s a vegan alternative to just about any meat product from beef burgers and chicken nuggets to hot dogs and breakfast sausages, the nutritional content may not be quite what you were hoping for. 

“People think that if it’s plant-based , it’s healthy or healthier, and that certainly can be, but it doesn’t necessarily have to be,” says D. Julian McClements, PhD, a distinguished professor of food science at the University of Massachusetts Amherst, whose research focuses on plant-based foods. “It really depends on [if] the company [is] designing it correctly.” 

What’s in plat-based meat? 

The global alternative meat, or meat analogue, industry is vast—valued at $18.78 billion in 2023 and projected to nearly double by 2032. 

Traditional veggie burgers are typically made of beans and vegetables that get mashed and pressed into a patty, allowing you to often see the whole foods—black beans, lentils, corn, chickpeas—that make up these products. But newer meat analogues, the most famous brands being Beyond and Impossible, much more closely resemble the meats they mimic than the distant plant cousins—pea protein for Beyond, soy for Impossible—from which their ingredients are aggressively extracted. 

“These are definitely ultra-processed products,” says McClements. “Ultra-processed can mean that something is less healthy for you, but it can also mean that it’s healthier than the alternative.”  

Is plant-based meat good for you? 

The more closely meat alternatives mimic real meat, the more processed they likely are. And that’s where you might run into problems. 

For starters, ultra-processing can rob otherwise good-for-you foods of their nutritional value. When whole foods are broken down and forced into other forms—whether it’s a corn chip or a soy patty—a lot of their natural fiber is lost, according to the American Medical Association . Lower-fiber foods digest more quickly, which causes a blood sugar spike and also doesn’t leave you feeling as satisfied as whole, unprocessed foods do. That’s ok for a treat now and then. But diets high in ultra-processed foods can lead to overeating, obesity, and diabetes. 

That’s the problem with any ultra-processed food. Fake meats in particular can have other problems. 

To make these meatless burgers greasy like a beef burger, you need fat, which usually comes in the form of added sunflower, coconut, or canola oil. That helps explain why some burger lookalikes have as much—and sometimes more— saturated fat , which can raise cholesterol levels, as a frozen all-beef patty. And they may log five times as much sodium. They also contain carbs, which can raise blood sugar, although some of those carbs are fiber, which is a good thing and an area where meat falls short. They tend to pack just as many calories as beef patties, too—about 2 to 2.5 calories per gram or 200 calories per 3.5-ounce patty. 

“You have to know what’s in them and compare them to what you’d be replacing,” says Judy Simon, RD, a dietitian in the Nutrition Clinic at UW Medical Center in Seattle. 

While side-by-side comparisons with plain frozen beef patties from your grocer’s freezer don’t differ much, these plant-based products may deliver a good bit less sodium and sugar than a hamburger from the major fast food chains, which might make them a wise option when eating out as opposed to cooking at home, if it is salt and sugar you are trying to avoid. Just beware, they don’t promise to save you any calories and, surprisingly, may contain even more fat.

What does the science say about plant-based meat?

Scientific research gives faux meat mixed reviews. 

In a small November 2020 study in the American Journal of Clinical Nutrition , researchers tracked a group of 36 adults for 16 weeks. For eight weeks, they had two servings of meat per day, such as pork, hamburgers, sausage and ground beef. For the other eight weeks, they had two daily servings of the Beyond brand counterpart instead of meat. Half the group did the meat diet first; the other half went veg first. Then they switched. Everything else stayed the same over the four months, including daily exercise and overall calorie intake. Still, during the eight-week fake meat diet, most people lost weight and saw a drop in their LDL (“bad”) cholesterol. 

But more recent studies haven’t been so positive. 

A 2024 study took the same eight-week approach. Only this time, it included 82 people. Half ate from a predetermined menu of meats the whole time. The other half ate the veggie version of each of those meats from various brands, including Impossible, Beyond, and others. The researchers checked everyone’s weight, cholesterol, blood sugar, blood pressure, and other health markers at the beginning and the end. 

The people in the plant-based group didn’t come out any better in the end than their meat-eating counterparts. 

But coming out “better” is not exactly the point of these burger lookalikes, says Sunil Chandran, Chief Scientific Officer at Impossible Foods. 

“Our products are not intended to be salads or veggie burgers,” he says. “Everything we make is designed to replicate the full sensory and nutritional experience of eating meat that meat-lovers crave, and more often than not, classic veggie burgers aren’t hitting the mark for these folks. Our goal is to offer a better option for meat eaters who are looking to incorporate more plant-based foods, but don’t want to change their lifestyle so drastically.”

Meat analogues don’t seem to help with inflammation, either. Chronic inflammation is a risk factor for many diseases, including heart disease , diabetes, Alzheimer’s and certain cancers, and past research has suggested that a meat-heavy diet causes inflammation. More recent research is shifting away from that conclusion, but researchers are still asking whether alt meats can counter inflammation. 

A small 2022 study in the American Journal of Clinical Nutrition says no. In it, the same 36 adults from the 2020 study showed very little difference in inflammation levels after eight weeks on alt meats and eight weeks on beef. 

The good news is: You have choices. If health is a concern, you have to look beyond the “plant-based” branding and read the label. Go for the options with more fiber and less sugar, fat and sodium.

Beyond Meat recently announced that they’ve reformulated their burger and ground beef alternatives to replace coconut and canola oils with avocado oil, bringing the saturated fat content down by 60% to just 2 grams per serving. The new formulation, scheduled to arrive in supermarkets in June, also cuts sodium by 20%. 

“It’s important to note that our products are similar to or lower in sodium than plain ground beef once you add salt or a seasoning blend [to plain ground beef], which most people do during the cooking process,” says Joy Bauer, RDN, nutrition advisor to Beyond Meat.

The changes to the formula, she says, “have garnered recognition from the American Diabetes Association, which certified our products as part of their ‘Better Choices for Life’ program, and the American Heart Association, which certified a collection of heart-healthy recipes featuring our products.”

Impossible, too, offers options with a better nutrition profile than its standout Impossible Burger, like Lite Beef, which also got a nod from the American Heart Association. “But not only is it a healthier product, it still tastes as meaty and delicious as lean animal beef – proving that heart-healthy choices don’t necessarily have to be less flavorful,” Chandran says. 

“A majority of our meat products contain at least 25% less total fat and saturated fat compared to the animal [product],” Chandran says. “And because our meat is made from plants, our products are higher in intrinsic fiber content than animal meat.”

It’s also important to note that a plant-based diet has been shown to lower the risk of diabetes, high cholesterol, dementia, depression, and some cancers—but just be sure to opt for whole foods over processed as often as possible.

Too soon to tell

Sugar, fat, sodium, calories, inflammation—all the devil you know. But meat analogues may also introduce a devil that even food and nutrition experts don’t know about yet. 

“We’ve been grinding up meat and making hamburgers for a hundred years,” says Youling Xiong , PhD, a professor of food and animal sciences at the University of Kentucky in Lexington. “But we just don’t have enough data to assess everything related to long-term consumption of plant-based meats.”

Nobody knows the potential health consequences of the new ingredients and processes that are unique to alt meats. 

“People don’t recognize the incredible complexity of creating these products,” McClements says. “Using plants to make something that looks or tastes exactly like meat is incredibly challenging and requires all sorts of biology, chemistry, and physics.” 

Impossible Foods, for example, pioneered the use of plant heme —an iron-rich molecule found in every living thing—to beef up the taste and smell of its burgers. In real meat, heme comes from hemoglobin found in blood. In Impossible meat, it comes from leghemoglobin found in legumes, specifically soy, from which Impossible derives heme in its manufacturing plants. 

“With plant hemoglobin, it behaves more or less the same as a meat product, and that’s what makes it go from red to brown when you cook it,” McClements says. 

Thanks to plant heme, at first glance, sniff, and maybe even first bite, an Impossible burger might fool even the most ardent carnivore. 

“It’s a genetically engineered product that we just don’t have enough history on to know whether, for example, people are going to be sensitive to it or just whether it’s OK,” Simon says.  

Future impact

But plant-based meat substitutes still do measurable good. Their manufacture uses less water and land, causes less water and air pollution, and produces fewer greenhouse gasses than meat production. They have about half the environmental impact of real meat. 

“Animal production cannot sustain the world’s population or the world climate,” Xiong says. “But plants we can grow, so sustainability is a driving force of this market.” 

As the plant-based protein market continues to grow, and processing advances, experts expect you’ll have healthier choices, too. 

“In the past, food scientists designed foods to be delicious, convenient, and affordable,” McClements says. “But this next generation of plant-based foods is where we’re trying to design health and sustainability as well.”

Most Popular

Diet Review: MIND Diet

Finding yourself confused by the seemingly endless promotion of weight-loss strategies and diet plans?  In this series , we take a look at some popular diets—and review the research behind them.

What Is It?

The Mediterranean-DASH Diet Intervention for Neurodegenerative Delay, or MIND diet, targets the health of the aging brain. Dementia is the sixth leading cause of death in the United States, driving many people to search for ways to prevent cognitive decline. In 2015, Dr. Martha Clare Morris and colleagues at Rush University Medical Center and the Harvard Chan School of Public Health published two papers introducing the MIND diet. [1,2] Both the Mediterranean and DASH diets had already been associated with preservation of cognitive function, presumably through their protective effects against cardiovascular disease, which in turn preserved brain health.

The research team followed a group of older adults for up to 10 years from the Rush Memory and Aging Project (MAP), a study of residents free of dementia at the time of enrollment. They were recruited from more than 40 retirement communities and senior public housing units in the Chicago area. More than 1,000 participants filled out annual dietary questionnaires for nine years and had two cognitive assessments. A MIND diet score was developed to identify foods and nutrients, along with daily serving sizes, related to protection against dementia and cognitive decline. The results of the study produced fifteen dietary components that were classified as either “brain healthy” or as unhealthy. Participants with the highest MIND diet scores had a significantly slower rate of cognitive decline compared with those with the lowest scores. [1] The effects of the MIND diet on cognition showed greater effects than either the Mediterranean or the DASH diet alone.

How It Works

The purpose of the research was to see if the MIND diet, partially based on the Mediterranean and DASH diets, could directly prevent the onset or slow the progression of dementia. All three diets highlight plant-based foods and limit the intake of animal and high saturated fat foods. The MIND diet recommends specific “brain healthy” foods to include, and five unhealthy food items to limit. [1]

The healthy items the MIND diet guidelines* suggest include:

• 3+ servings a day of whole grains
• 1+ servings a day of vegetables (other than green leafy)
• 6+ servings a week of green leafy vegetables
• 5+ servings a week of nuts
• 4+ meals a week of beans
• 2+ servings a week of berries
• 2+ meals a week of poultry
• 1+ meals a week of fish
• Mainly olive oil if added fat is used

The unhealthy items, which are higher in saturated and trans fat , include:

• Less than 5 servings a week of pastries and sweets
• Less than 4 servings a week of red meat (including beef, pork, lamb, and products made from these meats)
• Less than one serving a week of  cheese and fried foods
• Less than 1 tablespoon a day of butter/stick margarine

*Note: modest variations in amounts of these foods have been used in subsequent studies. [9,10]

This sample meal plan is roughly 2000 calories, the recommended intake for an average person. If you have higher calorie needs, you may add an additional snack or two; if you have lower calorie needs, you may remove a snack. If you have more specific nutritional needs or would like assistance in creating additional meal plans, consult with a registered dietitian. 

Breakfast: 1 cup cooked steel-cut oats mixed with 2 tablespoons slivered almonds, ¾ cup fresh or frozen blueberries, sprinkle of cinnamon

Snack: 1 medium orange

• Beans and rice – In medium pot, heat 1 tbsp olive oil. Add and sauté ½ chopped onion, 1 tsp cumin, and 1 tsp garlic powder until onion is softened. Mix in 1 cup canned beans, drained and rinsed. Serve bean mixture over 1 cup cooked brown rice.
• 2 cups salad (e.g., mixed greens, cucumbers, bell peppers) with dressing (mix together 2 tbsp olive oil, 1 tbsp lemon juice or vinegar, ½ teaspoon Dijon mustard, ½ teaspoon garlic powder, ¼ tsp black pepper)

Snack: ¼ cup unsalted mixed nuts

• 3 ounces baked salmon brushed with same salad dressing used at lunch
• 1 cup chopped steamed cauliflower
• 1 whole grain roll dipped in 1 tbsp olive oil

Is alcohol part of the MIND diet?

Wine was included as one of the 15 original dietary components in the MIND diet score, in which a moderate amount was found to be associated with cognitive health. [1] However, in subsequent MIND trials it was omitted for “safety” reasons. The effect of alcohol on an individual is complex, so that blanket recommendations about alcohol are not possible. Based on one’s unique personal and family history, alcohol offers each person a different spectrum of benefits and risks. Whether or not to include alcohol is a personal decision that should be discussed with your healthcare provider. For more information, read Alcohol: Balancing Risks and Benefits .

The Research So Far

The MIND diet contains foods rich in certain vitamins, carotenoids, and flavonoids that are believed to protect the brain by reducing oxidative stress and inflammation. Although the aim of the MIND diet is on brain health, it may also benefit heart health, diabetes, and certain cancers because it includes components of the  Mediterranean  and  DASH  diets, which have been shown to lower the risk of these diseases.

Cohort studies

Researchers found a 53% lower rate of Alzheimer’s disease for those with the highest MIND diet scores (indicating a higher intake of foods on the MIND diet). Even those participants who had moderate MIND diet scores showed a 35% lower rate compared with those with the lowest MIND scores. [2] The results didn’t change after adjusting for factors associated with dementia including healthy lifestyle behaviors, cardiovascular-related conditions (e.g., high blood pressure, stroke, diabetes), depression, and obesity, supporting the conclusion that the MIND diet was associated with the preservation of cognitive function.

Several other large cohort studies have shown that participants with higher MIND diet scores, compared with those with the lowest scores, had better cognitive functioning, larger total brain volume, higher memory scores, lower risk of dementia, and slower cognitive decline, even when including participants with Alzheimer’s disease and history of stroke. [3-8]

Clinical trials

A 2023 randomized controlled trial followed 604 adults aged 65 and older who at baseline were overweight (BMI greater than 25), ate a suboptimal diet, and did not have cognitive impairment but had a first-degree relative with dementia. [9] The intervention group was taught to follow a MIND diet, and the control group continued to consume their usual diet. Both groups were guided throughout the study by registered dietitians to follow their assigned diet and reduce their intake by 250 calories a day. The authors found that participants in both the MIND and control groups showed improved cognitive performance. Both groups also lost about 11 pounds, but the MIND diet group showed greater improvements in diet quality score. The authors examined changes in the brain using magnetic resonance imaging, but findings did not differ between groups. [10] Nutrition experts commenting on this study noted that both groups lost a similar amount of weight, as intended, but the control group likely improved their diet quality as well (they had been coached to eat their usual foods but were taught goal setting, calorie tracking, and mindful eating techniques), which could have prevented significant changes from being seen between groups. Furthermore, the duration of the study–3 years–may have been too short to show significant improvement in cognitive function.

The results of this study showed that the MIND diet does not slow cognitive aging over a 3-year treatment period. Whether the MIND diet or other diets can slow cognitive aging over longer time periods remains a topic of intense interest.

Other factors

Research has found that greater poverty and less education are strongly associated with lower MIND diet scores and lower cognitive function. [11]

Potential Pitfalls

• The MIND diet is flexible in that it does not include rigid meal plans. However, this also means that people will need to create their own meal plans and recipes based on the foods recommended on the MIND diet. This may be challenging for those who do not cook. Those who eat out frequently may need to spend time reviewing restaurant menus.
• Although the diet plan specifies daily and weekly amounts of foods to include and not include, it does not restrict the diet to eating only these foods. It also does not provide meal plans or emphasize portion sizes or exercise .

Bottom Line  

The MIND diet can be a healthful eating plan that incorporates dietary patterns from the Mediterranean and DASH , both of which have suggested benefits in preventing and improving cardiovascular disease and diabetes , and supporting healthy aging. When used in conjunction with a balanced plate guide , the diet may also promote healthy weight loss if desired. Whether or not following the MIND diet can slow cognitive aging over longer time periods remains an area of interest, and more research needs to be done to extend the MIND studies in other populations.

• Healthy Weight
• The Best Diet: Quality Counts
• Healthy Dietary Styles
• Other Diet Reviews
• Morris MC, Tangney CC, Wang Y, Sacks FM, Barnes LL, Bennett DA, Aggarwal NT. MIND diet slows cognitive decline with aging. Alzheimer’s & dementia . 2015 Sep 1;11(9):1015-22.
• Morris MC, Tangney CC, Wang Y, Sacks FM, Bennett DA, Aggarwal NT. MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s & Dementia . 2015 Sep 1;11(9):1007-14.
• Dhana K, James BD, Agarwal P, Aggarwal NT, Cherian LJ, Leurgans SE, Barnes LL, Bennett DA, Schneider JA. MIND diet, common brain pathologies, and cognition in community-dwelling older adults. Journal of Alzheimer’s Disease . 2021 Jan 1;83(2):683-92.
• Cherian L, Wang Y, Fakuda K, Leurgans S, Aggarwal N, Morris M. Mediterranean-Dash Intervention for Neurodegenerative Delay (MIND) diet slows cognitive decline after stroke. The journal of prevention of Alzheimer’s disease . 2019 Oct;6(4):267-73.
• Hosking DE, Eramudugolla R, Cherbuin N, Anstey KJ. MIND not Mediterranean diet related to 12-year incidence of cognitive impairment in an Australian longitudinal cohort study. Alzheimer’s & Dementia . 2019 Apr 1;15(4):581-9.
• Melo van Lent D, O’Donnell A, Beiser AS, Vasan RS, DeCarli CS, Scarmeas N, Wagner M, Jacques PF, Seshadri S, Himali JJ, Pase MP. Mind diet adherence and cognitive performance in the Framingham heart study. Journal of Alzheimer’s Disease . 2021 Jan 1;82(2):827-39.
• Berendsen AM, Kang JH, Feskens EJ, de Groot CP, Grodstein F, van de Rest O. Association of long-term adherence to the mind diet with cognitive function and cognitive decline in American women. The journal of nutrition, health & aging . 2018 Feb;22(2):222-9. Disclosure: Grodstein reports grants from International Nut Council, other from California Walnut Council, outside the submitted work.
• Chen H, Dhana K, Huang Y, Huang L, Tao Y, Liu X, van Lent DM, Zheng Y, Ascherio A, Willett W, Yuan C. Association of the Mediterranean Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) Diet With the Risk of Dementia. JAMA psychiatry . 2023 May 3.
• Liu X, Morris MC, Dhana K, Ventrelle J, Johnson K, Bishop L, Hollings CS, Boulin A, Laranjo N, Stubbs BJ, Reilly X. Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) study: rationale, design and baseline characteristics of a randomized control trial of the MIND diet on cognitive decline. Contemporary clinical trials . 2021 Mar 1;102:106270. Disclosure: several corporations generously donated mixed nuts (International Tree Nut Council Nutrition Research and Education Foundation), peanut butter (The Peanut Institute), extra virgin olive oil (Innoliva-ADM Capital Europe LLP), and blueberries (U.S. Highbush Blueberry Council). These items will be distributed to those participants who are randomized to the MIND diet arm.
• Barnes LL, Dhana K, Liu X, Carey VJ, Ventrelle J, Johnson K, Hollings CS, Bishop L, Laranjo N, Stubbs BJ, Reilly X. Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons. New England Journal of Medicine . 2023 Jul 18.
• Boumenna T, Scott TM, Lee JS, Zhang X, Kriebel D, Tucker KL, Palacios N. MIND diet and cognitive function in Puerto Rican older adults. The Journals of Gerontology: Series A . 2022 Mar;77(3):605-13.

Last reviewed August 2023

Terms of Use

The contents of this website are for educational purposes and are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The Nutrition Source does not recommend or endorse any products.