Turgor movements in plants

TURGOR MOVEMENTS

The movements which occur due to differential changes in turgor and cell size as a result of gain or loss of water are called turgor movements. Turgor movements are divided into further classes.

Sleep Movement
Rapid Movement

(i) Sleep Movement: The lowering of leaves in the evening and raising in the morning is termed as sleep movement.

Example: Bean plans of legume family (fabaceae) show this movement.

Reason of Lowering of Leaves: When turgor pressure decrease on the lower side of pulvinus, the leaves lower and go to ❝Sleepping❞ position, pulvinus is a swollen portion with parenchyma cells at the base of petiole.

Reason of Rising of Leaves: When turgor pressure increase on the lower side of pulvinus, the leaves rise and become horizontal.

(ii) Rapid Movement: The folding of the compound leaves due to rapid loss of turgor by cells at the base of petioles is known as rapid movement. It takes place in Mimosa plant when it is touched. It is reported that kᐩ ions more first, which causes water to leave the cell by exosmosis. Mimosa takes about the ten minutes to region the turgor and restore turgidity in cell of the leaves.