Question

Leaves of sensitive plants wilt and droop down on a slight touch. What mechanism brings this change?

Answer 1

Sensitive plants:

1. Sensitive plants respond to touch with the movement.
2. The leaves of the sensitive plants droop or fold when they are touched.
3. Example of a sensitive plant- Mimosa pudica

Reason for drooping of leaves in sensitive plants:

1. The folding or drooping of leaves in sensitive plants is due to a loss in turgor pressure at the base of the petioles (pulvinus).
2. Turgor pressure is the force that pushes the cell membrane against the cell wall within the cell.
3. Turgor pressure helps in maintaining the rigidity and structure of the plant parts such as leaves.
4. If a sensitive plant is touched, then within a few seconds loss of turgor pressure results in the drooping of all the leaflets.