Question

Give reason for the following:

The leaves of certain plants roll up on a bright sunny day.

Answer 1

Rolling up of leaves:

1. It is the curling of the leaves.
2. Pest, viral infection, lack of vital nutrients, bad positioning of the plant and inadequate watering can be the reasons for leaves to roll up.
3. In some plants, leaves also roll up to reduce the rate of transpiration.

Leaf rolling reduces transpiration:

1. The lesser the effective surface area available, the lower is the rate of transpiration.
2. Leaves of some plants roll up on a bright sunny day to reduce the effective surface area for transpiration.
3. The reduced surface area ultimately reduces the rate of transpiration.