Role of Essential Plant Nutrients and Deficiency symptoms of macro nutrient in plants.
Major roles of plant nutrients in plants growth and development are -
1. Structural components of cell constituents and its metabolically active compounds.
2. In the maintenance of cellular organization e.g. Turgidity etc.
3. In energy transformation and In enzyme action.
Nitrogen
Nitrogen is the essential constituent of protein, nucleic acid, nucleotide, amino acid, chlorophyll, phospholipids, alkaloids, enzymes, hormones, vitamins etc. Imparts dark green color to plant.
Deficiency of Nitrogen provokes the synthesis of Anthocyanin which gives different types of coloration. (Compost contains high amount of nitrogen which is mainly used for horticultural and ornamental flowers because it is economical and helps in their physiology like proper color, size etc.) The content of N in healthy plants ranges between 1 - 5% upon the species or variety.
Phosphorous.
Due to deficiency of single element phosphorus, plants can not complete their life cycle hence 'p' is called key to life. Nitrogen governs the above earth growth whereas 'P' governs the root growth i.e. below earth growth. constituent of nucleic acid, phospholipids, ATP, and essential of reproductive functions; stimulates early root growth. Excess of P may cause in some cases the deficiency of trace elements particularly Fe and Zn.
Potassium
potassium does not enter into the composition of any of the important plant constituents. It is present in a plant in a state of solution in cell sap. Imparts disease resistance produces strong stiff especially in rice and wheat. Regulates water balance, better utilization of available water essential in the formation and transfer of starches and sugars thus required in large quantity for potato, sweet potato, turnip, banana, improves the quality of tobacco leaf, quality of fiber, size and keeping quality of fruits. In citrus fruits, however an excess of K has a bad effect on quality. K (potassium) regulates osmo-regulation, and stomatal movement. it acts as root booster, stalk strengthener, food former, sugar and starch transporter, protein builder, breathing regulator.
Calcium
calcium is the Constituent of middle lamella of cell-wall which gives turgidity of cell highly required in Telophase for cell plate formation. Structural component, neutralize organic acids, essential in activated the growing point especially root tips.
General Deficiency symptoms are÷
Element
1) Nitrogen
• Chlorosis in old leaves
• Reduced tillering in cereals
• In acute deficiency whole crop appears yellowish and growth is stunted.
2) Phosphorus
• Stunted growth.
• Purple orange color of the older leaves.
• Younger leaves dark green.
• Tillering reduced drastically.
3) Potassium
• Older leaves show spots of burn starting from tips.
• Increased susceptibility to diseases, drought, salinity and cold injuries.
4) Calcium.
• Younger leaves become white.
• Growing point die and curl.
• Magnesium Marginal or inter-venal chlorosis with pinkish color of older leaves Stress.
• susceptibility increased.
5) Sulphur
• Chlorosis in younger leaves.
• Under severe deficiency whole plant becomes chlorotic.
• Leaves are similar to appearance as in Nitrogen deficiency.
5) Zinc
• Rusting in strip of older leaves.
•Chlorosis in matured leaves.
•Reduced leaf size.
6)Iron
• Inter-venal chlorosis in younger leaves.
• Under severe deficiency the whole leaf turn to yellow.
• At advance stage necrosis develops instead of white color.
7) Copper
• Chlorosis in young leaves.
•Leaf rolling
• dieback.
8)Molybdenum
•Young leaves appears mottled pale.
•Bleaching and withering of leaves.
9)Boron
•Pale green tips of blades.
•Death of growing point.