Question

Leaves that appear wilted in day time recover at night because

• A. Light is essential for photosynthesis.
• B. The stomata close down, temperature decreases and transpiration is reduced and plant is able to absorb more water from the soil.
• C. Respiration and translocation of organic substances increases.
• D. None of the above

Answer 1

The correct option is B The stomata close down, temperature decreases and transpiration is reduced and plant is able to absorb more water from the soil.

Wilting of leaves occur in response to plasmolysis, when plant cells lose lot of water due to exosmosis. During day time, when temperature is high, there is high transpiration if plants are not able to absorb enough water the leaves will wilt. After sunset the temperature and consequently rate of transpiration drop. Hence, there is less water loss from plants and plants generally overcome the wilt.