Explain with examples: macronutrients

Hint: The nutrients that are present in large amounts in plant tissues that is in excess of \[10mmole{\text{ }}k{g^{ - 1}}\]of dry matter are called as macronutrients . These elements are present in detectable quantities in plants and can easily be detected. These are of nine types mainly.

Complete answer:
Let us now study the various forms and functions of essential mineral elements in detail.
Nitrogen: This is the mineral element required by plants in the greatest amount.
Absorption: It is absorbed mainly as \[NO\]- or $\mathop {NH}\nolimits_4^ + $
Requirement: Nitrogen is required by all parts of a plant, particularly the meristematic tissues and the metabolically active cells.
Physiological role: Nitrogen is one of the major constituents of proteins, nucleic acids, vitamins and hormones. Being a component of such a large number of biomolecules, nitrogen is essential for all types of metabolic activities, photosynthesis, respiration, cell growth cell division.
. Phosphorus:
Absorption : It is absorbed in the form of phosphate ions from the soil.
Requirement: Inside the plant, phosphorus is stored in developing fruits, seeds, storage organs and young meristematic tissues.
Potassium:
Absorption : It is absorbed as K+
Physiological role: It helps to maintain an anion-cation balance in cells. It is involved in protein synthesis.

There are other macronutrients also namely
Carbon
Hydrogen
Oxygen
Sulphur
Magnesium
Calcium

Note: Macronutrients build up the plant body and different protoplasmic constituents. They do not become toxic in slight excess. The macronutrients are absorbed from soil . They are usually involved in the synthesis of organic molecules. Carbon , hydrogen and oxygen are obtained from carbon dioxide and water. Nutrients which are required in large quantities by plants.