Role of Macronutrients and Micronutrients

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Macronutrients in Plants

Plants are living organisms and they also require nutrients like us in order to survive, grow, reproduce and develop. Macronutrients in plants are nutrients that provide energy to the plants and are required in larger amounts to maintain their development and growth. These are the most important elements required for crops and examples include Nitrogen (N), Potassium (K), Calcium (Ca), Phosphorus (P), Magnesium (Mg), Sulphur (S), Oxygen (O), Carbon (C) and Hydrogen (H). Out of these the most important ones are Nitrogen, Phosphorus and Potassium, which directly affects plant growth and actually creates various parts of the plant. Also, Nitrogen is an important component of chlorophyll that plays a vital role in photosynthesis (food synthesising process).


Micro and Macro Nutrients in Plants

In addition to macronutrients, micronutrients are the other category of nutrients that are called trace elements or minerals required in a very small quantity that help in growth or metabolism. We will discuss all macro and micro elements and their functions in detail further.


Some important micronutrients include Boron (B), Iron (Fe), Chlorine (Cl), Manganese (Mn), Copper (Cu), Zinc (Zn), Molybdenum (Mo) and Nickel (Ni).


Role of Macro and Micronutrients

Macronutrients and micronutrients in plants fall under Essential Nutrients that support plants for all biochemical needs and without which:

  • A plant can’t complete its life cycle.

  • Other element can’t replace a specific function for plant.

  • Plants cannot get full nutrition as each essential nutrient is directly involved in plant nutrition.

Out of all the essential nutrients, about half of the elements are considered as macronutrients and functions of macronutrients are very necessary, for example, Carbon is required to form proteins, carbohydrates, nucleic acids and other compounds or key plant macromolecules.


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List of Macronutrients and Micronutrients

Macronutrients

Micronutrients

Carbon (C)

Iron (Fe)

Hydrogen (H)

Manganese (Mn)

Oxygen (O)

Boron (B)

Nitrogen (N)

Molybdenum (Mo)

Phosphorus (P)

Copper (Cu)

Calcium (Ca)

Chlorine (Cl)

Potassium (K)

Zinc (Zn)

Magnesium (Mg)

Nickel (Ni)

Sulphur (S)

Cobalt (Co)


Sodium (Na)


Silicon (Si)


All the elements are important for plants, some in larger quantities called macronutrients and some in lesser or minute quantities called micronutrients.


Functions of Macronutrients and Micronutrients

It is good to know the structure and functions of macro and micro nutrients for gaining information about these in a better way and recognize the role of each of them. Let’s know the functions they perform in the plants one by one for macro and micronutrients:

  • Macronutrients in Plants and Their Functions

The most important crop nutrients are Nitrogen, Phosphorus and Potassium that affect plant growth directly and create various parts of plants.

  1. Nitrogen

It is important to plants for:

  • Metabolism as it is an important substance and part of amino acids, proteins and enzymes.

  • Influences germination and vegetative growth.

  • Being a component of chlorophyll, it plays an important role in photosynthesis.

  • Responsible for rapid growth of foliage.

  • Provides green color to the plants.

Deficiency of Iron in plants results in stunted crop growth, chlorosis or yellowing of leaves, weakness during fruiting and flowering, leading to lower yields.


Too much nitrogen is also not good for plants as it causes dark green colouring of leaves, lush growth, crop lodging and fruit quality reduction.

  1. Phosphorus

It is important to plants for:

  • Development of roots.

  • Maintaining good quality of flowering, fruiting and seed production.

  • Storing and transporting energy.

  • Resistance to disease.

Deficiency of Phosphorus leads to stunted plant growth, weakened roots, thin shoots and dark green/purple/red leaves. Excessive amounts of Phosphorus can cause lower reception and deficiency of other elements like Zn, Fe, Cu, Mn and B.

  1. Potassium (K)

It is important to plants for:

  • Influencing water uptake.

  • Improving drought tolerance.

  • Improvement in cold hardiness.

  • Providing resistance to fungal diseases and insect pests.

  • Synthesizing proteins, sugar and fat.

Deficiency of Potassium in plants leads to growth reduction, burning or yellowing of the leaf margins and dead spots on older leaves. Excess amounts are also not so beneficial as they affect the uptake of other nutrients including magnesium, calcium and nitrogen.

  • Micronutrients in Plants and Their Functions

Boron, Iron, Manganese and Zinc are the most important micronutrients in a plant organism. Let’s find out :

  1. Boron

It is important for:

  • Sugar transport

  • Amino acid production

  • Cell wall formation

  • Crop reproduction

  • Fruiting

  • Flowering.

  • Improvement of crop quality.

Boron deficiency in plants can show various symptoms that include stunted growth of young crops, deformation of leaves, death of growing points, dark brown lesions on leaves, poor flowering and chlorosis or yellowing of leaves. It should be ensured that Boron application should be before the flowering stage in crops, applying later is not beneficial. 

  1. Iron (Fe)

Iron is important for:

  • Chlorophyll production.

  • Photosynthesis

  • Enzyme composition.

  • Influences energy transfer, nitrogen reduction and fixation.

  • Lignin formation.

Deficiency in iron in plants harms younger leaves as it causes yellowing between the veins.

  1. Manganese (Mn)

It is important to plants for:

  • Influences chloroplast production.

  • Actively Participating in photosynthetic process.

  • Activation of enzymes and influencing germination plus crop maturity.

Deficiency in Mn also may lead to yellowing of veins in the younger leaves called chlorosis.

  1. Zinc

It is important to plants for:

  • Early growth stages.

  • Development of root, seed and fruit.

  • In the process of photosynthesis.

  • Balancing plant hormones.

  • Activity of auxins.

Deficiency of Zinc results in stunted growth, length reduction of internodes, smaller young leaves, and yellowing on the lower leaves.

FAQ (Frequently Asked Questions)

1. Explain the Role of Micronutrients in Plants.

Ans. Micronutrients equally play an important role in plant growth as macronutrients. They perform specific functions which are much required for the development of plants. Example- Zinc and copper help in the activation of certain enzymes, pollen germination, cell elongation, utilization of calcium and proper functioning of the membranes. Chlorine aids in determination of the solute concentration and balancing the anion-cation of the cells.

2. What are the Macronutrients for Plants?

Ans. Macronutrients for plants are the essential nutrients which are required in larger quantities by the plants. Examples include Sodium, Phosphorus, Potassium, Carbon, Hydrogen, Oxygen, Magnesium and Sulphur.