Question

The wilting of plants result due to excess of
a. Absorption
b. Photosynthesis and poor osmosis
c. Respiration
d. Transpiration

Answer 1

Hint: Wilting is the loss of rigidity of non-woody parts of the plant. In the case of a normal plant, the rate of absorption of water is equal to the rate of transpiration. But sometimes the rate of water absorption by plants somehow decreases, causing excess water loss through plants. This results in the wilting of plants.

Complete answer:
The wilting of plants occurs when turgor pressure (turgor pressure is the pressure exerted by the fluid on the wall of its container) in the non lignified plant cells becomes zero. Lignin is particularly the important organic molecule which is important in the formation of cell walls, especially in wood and bark because they provide rigidity to the structure and do not rot easily. The lack of water causes the turgor pressure to drop zero.

When turgor pressure drops zero, it means there is no water left in the cell which will keep it flaccid. Wilting diminishes the plant’s ability to grow and transpire. If wilting persists for a long time it may lead to plant death.

Wilting may be caused due to low water availability to plants due to some reasons such as drought where soil moisture content may drop below the normal level. Lower temperature also leads to low functionality of plants' vascular systems.

Another reason may be the high salinity of the water which causes diffusion of water leading to shrinkage of cells and bacterial or fungal infections that may have clogged the vascular system.

Hence, The correct answer is, option (D).

Note: The phenomenon of wilting of plants is an effect of plant growth inhibiting hormone known as abscisic acid. When the abscisic acid is released in the plants, plants try to recover to its original state. Wilting reduces water loss from the leaves by making the leaves to expose less surface area to minimize transpiration.