MACRO NUTRIENTS: 1, 2, 3 - Carbon, Hydrogen and Oxygen: These three elements are referred to as frame work elements. These elements constitute the major part of dry weight of the plant Carbon 45%, Oxygen 43%, and Hydrogen 6%. These elements are not mineral in origin. They enter into composition of all organic compounds of the plants. They are taken up by plants in the form of 〖CO〗_2 and water. Carbon is absorbed in the form of 〖CO〗_2 from air. It is essential for the synthesis of carbohydrates and fats which build the cell wall, protoplasm etc. Hydrogen & Oxygen are present in water which is absorbed by the plant from the soil. Water is indispensable for various vital activities in the plants.
4. Nitrogen: 1.5% Source: soil and atmosphere bacteria and blue green algae and utilize atmospheric N_2. Obtained as: Nitrates, Nitrites and Ammonium salts.Functions: Nitrogen is a component of proteins (essential for protein synthesis), amino acids, nucleic acids, chlorophyll, cytochrome enzymes (photosynthesis and respiration), alkaloids, plant harmones, and vitamins.Deficiency symptoms: Deficiency of Nitrogen leads to: 1 Chlorosis 2 Depreciation of Anthocyanin pigment. 3 Flowering is delayed. 4 Fruits underdeveloped.
5. Phosphorus: 0.2% Source: Soil in the form of H_2 〖po〗_4^- and H〖po〗_4^(2-) Component: It is a component of nucleic acids, nucleoproteins, phospholipids, ATP, NADP. Highest amount is present in meristematic parts, maturing seeds and fruits. Functions: Synthesis of nucleoproteins and important in processes like photosynthesis and respiration. Deficiency symptoms:Deficiency of Phosphorus leads to: 1 Stunted growth. 2 Dead necrotic spots on leaves. 3 Depreciation of anthocyanin pigment 4 Flowering is delayed.
6. Potassium: 1% of dry weight Source: plants absorb potassium in the form of K^+. Potassium is not a constiluent of compound. Functions:It is an activator of many enzymes (pyrmic kinase which is respiratory enzyme requires K^+ for activity. It maintains ionic balance in cells. It regulates stometel movement. Deficiency symptoms: Deficiency of Potassium leads to: 1 Mottled chlorosis. 2 Necrotic spots. 3 Growth is reduced, internodes become shortened and plants become stunted.
7. Calcium: 1% of dry weight. Source: soil in the form of 〖Ca〗^(2+)
Functions: It is important in synthesis of middle lamella of cell wall.It is associated with phospholipids of cell membranes. It is necessary for maintenance of permeability of membranes.It is an activator of enzymes like amylase.It is necessary in small amounts for mitosis.Deficiency symptoms:Deficiency of Calcium leads to:Rapid death of growing regions.Malformation of young leaves.Chlorosis of young leaves along margins.Stunted roots. Reduced flowering and fruiting.
8. Magnesium: 0.2% of dry weight Source: soil, it is absorbed as 〖Mg〗^(2+)Functions of Magnesium: 1 Component of chlorophyll.2 Controls binding of 2 sub units of ribosomes during protein synthesis. 3 Activator of enzymes for photosynthesis and respiration.
Deficiency symptoms of Magnesium: 1 Interveinal chlorosis. 2 Appearance of brightly coloured pigments. 3 Necrosis of older leaves.

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