Nutrition in Plants: Role and Deficiency Symptoms

Nutrition is the process by which living organisms take their food for maintaining proper growth, metabolisms and replacement of tissue.  Plants nutrition occurs in two phases such as synthesis and assimilation.  Generally, plants nutrition is of two types such as autotrophic plant nutrition and heterotrophic nutrition.

Autotrophic Plant Nutrition

In autotrophic nutrition, the plant gains simple and inorganic food elements in the form of liquid and gases. In this case, plants obtain energy needed for synthesis of food from the sun. The process by which glucose is synthesized from CO2 and H2O in the presence of sunlight by the help of chlorophyll is known as photosynthesis.

image of photosynthesis equation

Photosynthesis Equation

Glycerol, fatty acids, amino acids, and other carbohydrates are synthesized from glucose and are stored up complex forms in the leaves, stems, and roots for future use. These stored materials can be transformed into simple soluble foods by specific enzymes and later on the digested food materials are assimilated to form protoplasmic constituents.

The nutritional requirements of autotrophs include several inorganic ions. These are obtained from the surroundings and are called essential elements.

Heterotrophic Plant Nutrition

Plants which are devoid of chlorophyll are incapable of producing their own food within their body, known as heterotrophic plant nutrition. In this case, plants depend on green plants for their nutrition. In these plants, the mode of digestion is extracellular. Heterotrophic plant nutrition is of following types:

Parasitic Nutrition: The process by which a plant obtains its necessary nutrition from any other plants or animals is known as parasitic nutrition. 

Saprophytic Nutrition: The nutrition of certain non-green plants which extract their nourishment from the dead and decomposed organic substance formed as a result of the decay of plants and animals is called saprophytic nutrition. e.g. Agaricus.

Symbiotic Nutrition: When two organisms live in close association with each other for their mutual benefit in nutrition, then the type of nutrition is called symbiotic nutrition. Each of the pair is called symbiont and the mode of their association is known as symbiosis. e.g. Rhizobium living in the root nodules of leguminous plants are capable of fixing atmospheric nitrogen to help in ammonia production, which is taken by the leguminous plants and in lieu of which they supply carbohydrate food to the symbiotic bacteria, Rhizobium. Symbiotic nutrition also lies between plants and animals such as Zoochlorella and Hydra. Symbiotic nutrition is of two types:

(1) Mutualism: When two plants live in close association for mutual benefit in obtaining their nutrition, the type of nutrition is known as mutualism. e.g. Lichen. This formed between algae and fungus whereas the fungus extracts in carbohydrate type of food matters and oxygen from the algae. In this case, the fungus protects the algae from drying up.

(2) Commensalism: When two plants living together to obtain their nutrition independently then the type of nutrition is known as commensalism. This type of plants does not affect their hosts as they are capable of preparing their own food. e.g. Ficus (Banyan tree).

Plant Nutrients

Plants nutrients are the chemical substances which are essential for the proper growth of the plant. It is divided into two types on the basis of requirements by the plants such as macro- and micronutrients. There are many factors which influence the uptake of nutrients for plants. Plants receive mineral nutrients by absorbing with the help of roots as ions in soil water. Each of the nutrients plays an important role in plant health and growth.

Essential elements which are required in large amounts are called macroelements. Whereas the elements which are required in minute quantities or traces are called trace elements. These elements help the plants for proper growth and nutrition. In the absence of any of nutrient elements, normal growth of the plant is disturbed and different deficiency symptoms are exhibited by the plants. Plants require about 90 nutrient elements. Among them, 16 elements are distinguished as essential for plants. 

Carbon(C)AtmosphereIron (Fe)Soil, iron sulfate, iron chelate.
Hydrogen (H2)Soil, WaterManganese (Mn)Soil
Oxygen (O2)Soil, WaterZinc (Zn)Soil, zinc oxide, zinc sulfate, zinc chelate.
Nitrogen (N2)Soil organic matters, fertilizersCopper (Cu)Soil
Phosphorous (P)Soil organic matters, fertilizers, mineralsBoron (B)Soil, organic matter and borax
Potassium (K)Soil organic matters, fertilizers, mineralsMolybdenum (Mo)Soil
Calcium (Ca)Minerals, fertilizers, limeCobalt (Co)Soil
Magnesium (Mg)Minerals, fertilizers, limeChlorine (Cl)Soil
Sulfur (S)Soil organic matters, fertilizers, minerals

Macroelements, Their Role and Deficiency Symptoms in Plants

Carbon (C)

Role of Carbon in plants: 
  • Carbon compounds are formed due to photosynthesis.
  • Carbon is essential for the formation of the plant body.
  • It helps in fat and protein synthesis.
Deficiency Symptoms of Carbon in Plants:
  • Reducing plant growth;
  • Disturbing protein and fat synthesis;

Oxygen (O2)

Role of Oxygen in Plants
  • All the food matters of the plants are made up of oxygen. Through the process of oxygen fixation, some of the atmospheric oxygen is incorporated into some inorganic components.
  • Oxygen is essential during aerobic respiration for oxidation of the food. Hence, it acts as an oxidant during aerobic respiration.
Deficiency Symptoms Oxygen in Plants
  • Disturbing aerobic respiration;

Nitrogen (N2)

Role of Nitrogen in Plants
  • Nitrogen is a structural component of many coenzymes such as NAD, NADP, FAD, etc. Certain bacteria and blue-green algae can utilize gaseous nitrogen directly. They transfer nitrogen to nitrate ions (NO3). Higher plants obtain this nitrogen from the soil in the form of nitrates. vitamins, chlorophylls, coenzymes, etc.
  • It is essential for plant growth and photosynthesis.
  • It also affects the anabolic and catabolic reactions in plants.
  • It helps to form protein molecules.
Deficiency Symptoms of Nitrogen in Plants
  • Due to lack of nitrogen, general chlorosis occurs in the leaves. In this case, leaves become yellow, light tan and finally leaves die. 
  • Sometimes purplish coloration appears in stems, petioles, and lower leaf surfaces.

Hydrogen (H2)

Role of Hydrogen in Plants
  • For organic substances, hydrogen is an essential element.
  • The main component of the cytoplasm of the cell is water which contains hydrogen.
  • It helps on seed germination, seedling growth, adventitious rooting.
  • LIt enhances anthocyanin synthesis.
  • It also enhances plant symbiotic stress resistance;
Deficiency Symptoms of Hydrogen in Plants
  • Reducing plant growth;
  • Disturbing seed formation;

Phosphorous (P)

Role of Phosphorous in Plants
  • This occurs in nucleic acids, phospholipids, coenzymes like NAD, NADP, FAD, etc and energy compounds like ATP, GTP etc.
  • Phosphorous-containing compounds are involved in photosynthesis.
  • It helps  in seed formation and generates early root formation and growth of the plant;
  • It boosts up the fruit quality;
  • It helps to plant to survive in severe winter conditions.
  • It helps to transfer energy to plants.
  • Phosphorous helps in cell division and cell enlargement.
Deficiency Symptoms of Phosphorous in Plants
  • The deficiency symptoms are stunted growth; leaves turn dark blue-green, and chlorosis of leaves.
  • Dead necrotic areas appear on the leaves, petioles, and fruits.
  • Leaves fall down and purple or red anthocyanin pigmentation occurs in leaves.
  • Under phosphorous deficiency conditions, the older leaves become dark brown.
  • The shape of the leaves becomes a distortion.
  • Lots of pith and small amounts of vascular tissues are found in the stems.
  • Accumulation of carbohydrates occurs.

Sulfur (S)

Role of Sulfur in Plants
  • Sulfur is a component of protein, especially enzymes, biotin, coenzyme A, etc
  • It is an essential element of Amino acid.
  • Sulfur-containing compounds take part in respiration, lipid synthesis
  • It helps in the formation of enzymes and vitamins.
  • It influences seed formation and chlorophyll formation.
Deficiency Symptoms of Sulfur in Plants
  • Leaves turn yellow from green (chlorosis);
  • Roots develop extensively;
  • Red or purple coloration occur due to anthocyanin pigmentation.
  • Leaves fall takes place rapidly.
  • Margin and tips of the leaves are rolled inwards.
  • Protein and chlorophyll synthesis decreases.
  • Stems become short and hamper the growth of the plant.

Calcium (Ca)

Role of Calcium in Plants
  • Calcium is absorbed from the soil in the form of calcium ions. It occurs in the middle lamella of the cell wall.
  • Calcium acts as an activator of many enzymes.
  • It plays an important role in plasma membrane organization, mitosis, chromosomal stability, etc.
  • It takes part in nitrogen metabolism.
  • The decrease in plant respiration.
  • It boosts up nut development in some fruits.
Deficiency Symptoms of Calcium in Plants
  • Dying out of meristems;
  • Chlorosis in the margin of young leaves;
  • Rolling of the leaves;
  • Roots poorly develop,  become short, and brown;
  • Brown spots occur in fruits;
  • Pit formations in fruits;
  • Distortion of the growing shoot tips;

Magnesium (Mg)

Role of Magnesium in Plants
  • It acts as an activator of the enzyme.
  • It involves protein synthesis, nucleic acid synthesis, and carbohydrate metabolism.
  • It helps in chlorophyll formation.
  • It helps in the utilization of phosphorus mobility in plants.
  • It perks up the utilization of iron in plants.
Deficiency Symptoms of Magnesium in Plants
  • Due to its deficiency mottled chlorosis occurs;
  • Leaves become brittle and appearance of necrotic spots on leaves;
  • Leaf margins changes to reddish purple in color;
  • Photosynthesis and enzyme activities reduce;
  • It causes aging of leaves;
  • Extensive chlorenchyma development and scanty pith formation occurs;

Potassium (P)

Role of Potassium in Plants
  • It is an essential element for protein synthesis
  • It activates the certain enzyme and also takes part in carbohydrate and protein synthesis.
  • Enhance the translocation of starch.
  • It boosts up the seed and fruit quality.
  • It improves disease resistance capacity.
Deficiency Symptoms of Potassium in Plants
  • Lacks of potassium causes marginal chlorosis in leaves.
  • Potassium deficiency also affects the process of respiration, photosynthesis and chlorophyll synthesis.
  • Reduction in growth rate;
  • Reducing Protein level.
  • Mottled chlorosis  and dark necrotic lesions occur at the tip and margins of the leaf ;
  • Plant exhibits stunted growth with shortened internodes;
  • The disintegration of pith cells and formation of secondary phloem;

Microelements, Their Role and Deficiency Symptoms in Plants

Iron (Fe)

Role of Iron in Plants
  •  It is an essential element for respiratory reactions.
  • Iron plays an important role in overall metabolism in plants.
  • It also takes part in the synthesis of chlorophyll and respiration.
  • It acts as a carrier of oxygen;
  • It boosts up cell division and growth of plants.
  • It increases photosynthesis activity.
Deficiency Symptoms of Iron in Plants
  • Its deficiency symptom is chlorosis in leaves which is predominant in the younger leaves.
  • Chlorophyll production decreases;
  • Leaves become whitish yellow in color.
  • Plant growth becomes reduce;
Boron (B)
Role of Boron in Plants
  • It helps in the production of sugars and carbohydrates;
  • It enhances the fruit and seed development;
  • It controls the use of other nutrients;
  • It helps in the formation of cell membranes.
  • It helps in the transportation of sugar;
Deficiency Symptoms of Boron in Plants
  • Terminal leaves to turn white and internodes become shorten;
  • Due to deficiency of boron, abscission of flower, the death of roots and shoot tips take place;

Copper (Cu)

Role of Copper in Plants
  • It boosts up the plant reproduction;
  • It helps in the metabolism of the root;
  • It helps in protein utilization;
  • It activates enzymes and catalytic reactions for plant growth;
  • It helps in photosynthesis;
Deficiency Symptoms of Copper in Plants
  • Deficiency of copper causes wilting of terminal shoots, and fading of leaf colors;

Manganese (Mn)

Role of Manganese in Plants
  • It helps in the breakdown of carbohydrates;
  • It helps in nitrogen metabolism;
  • It acts as an activator of certain enzymes;
  • It takes part in photosynthesis, respiration, nucleic acid synthesis, and nitrate reduction;
Deficiency Symptoms of Manganese in Plants
  • Its  deficiency causes mottled chlorosis of leaves;
  • Chloroplasts become yellowish green, vacuolated and finally disintegrate;

Zinc (Zn)

Role of Zinc in Plants
  • It helps in the transformation of carbohydrates;
  • It controls the consumptions of sugars;
  • It regulates plant growth;
  • It acts as an activator of many enzymes;
Deficiency Symptoms of Zinc in Plants
  • Reducing plant growth
  • Leaves become yellowish in color due to chlorosis;
  • Leaves become narrow with heavy wavy margin 

Molybdenum (Mo)

Role of Molybdenum in Plants
  • It takes part in nitrogen fixation;
  • It acts as an activator of many enzymes;
Deficiency Symptoms of Molybdenum in Plants
  • Its deficiency causes the stoppage of development of leaf blade and chlorosis of leaves;
  • Flower formation is inhibited;
  • Marginal necrosis occurs in leaves;

Cobalt (Co)

Role of Cobalt in Plants
  • It acts as growth promotor ;
  • It is essential micronutrients and plays an important role in the overall plant growth;
  • It is a primary constituent of vitamin B12;
  • It helps in the cell division during plant growth;
Deficiency Symptoms of Cobalt in Plants
  • Reducing or stunting plant growth;
  • Reducing seed germination;

Chlorine (Cl)

Role of Chlorine in Plants
  • It is essential for photosynthesis;
  • It influences plant development;
Deficiency Symptoms of Chlorine in Plants
  • Its deficiency causes wilting of the leaf tips due to chlorosis;

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