Question

explain how osmotic pressure, functionjng of stomata and carbohydrates metabolism in green plants are physiological changes that occur due to drought

Answer 1

The normal functions of a green plant is not able to re-establish when that plant is exposed to severe drought.

Osmotic pressure changes that occur during drought are:-

During the humid period, the osmotic pressure increases with low humidity. There is large difference in osmotic pressure is seen between the roots and the leaves. The osmotic pressure is increased along with the increase in dryness. Resistance to desiccation is provided by higher osmotic values. Loss of water by the green plant stimulates lowers the osmotic pressure.

Changes in stomata function during drought are:-

The stomata lose its normal function or may die by open partially or slightly. Sometimes the leaves are appeared to be normal but the stomata remains in the inactive mode. The drought stimulates the sugar transformation to starch, then the starch in the guard cells of stomata decomposes. the drying stimulus causes the gradual decline and disappearance of starch.

Changes in carbohydrate metabolism during drought are :-

The drought intensifies the decomposition and starch get disappeared from the wiltered leaves. Carbohydrates accumulation is based on several factors. Nitrogen availability, sufficient moisture availability etc. During drought, moisture content will be less, then the interrupted growth and accumulation of polysaccharides is occured. Then the carbohydrate degradation in leaves along with its deposition in roots are seen. So we can say that, during drought the starch breakdown and disappearance is seen mainly in the leaves of the green plant.