Question

‘Sickle leaf disease’ occurs due to deficiency of:
(a) Mg
(b) P
(c) K
(d) Cu

Answer 1

Hint: The deficiency of this substance usually displays symptoms like general stunting of the plant during early growth. This can be observed on the lower portion chlorosis (yellowing) at the leaf margins that occur on the plant followed by necrosis (death of cells or tissue). Young plants remain stunted with dark blue-green or sometimes purplish leaves.

Complete answer:
Sickle leaf disease is caused due to deficiency of phosphorus, which is characterized by chlorosis adjacent to main veins followed by leaf asymmetry. A plant is said to be diseased when it is continuously disrupted by some causal agent that results in an abnormal physiological process that disturbs the plant’s normal structure, function, or other activities. Phosphorus is obtained from phosphate rock for commercial fertilizers.

Additional information:
Some other symptoms caused by a deficiency of P are:
- P deficiency may cause premature leaves to fall off the plant.
- Dead necrotic areas are developed on leaves and fruits.
- Leaves sometimes develop anthocyanin in veins and may become necrotic; leaves will be dark green in color in this case.
- We can see cambial activity in the plants.
- Tillering (production of side shoots) of crops is reduced.
- Dormancy is continued instead of the normal growth of the plant.

So, the correct answer is ‘Phosphorus.’

Note: Sprinkling 2% DAP or introducing more P into the soil with bone meal, rock phosphate, manure, Phosphoric fertilizers will correct the deficiency of P. Phosphorus is associated with plant's ability to use and store energy, it helps plants grow and develop normally, also is related to the process of photosynthesis.