Question

The leaves of the 'chhui-mui' plant begin to fold up and droop in response to a stimulus. Name the stimulus and write the cause for such a rapid movement. Is there any growth involved in the movement?

Answer 1

The leaves of the 'chhui-mui' plant, also known as the 'sensitive' or 'touch-me-not' plant of the Mimosa family, begin to fold up and droop in response to touch.

This movement is an immediate response to the stimulus of touch and does not involve growth. Unlike animals, plants lack nervous and muscle tissue, so they rely on electrical-chemical means to convey information from cell to cell.

In response to touch, certain plant cells change shape by altering the amount of water within them, resulting in swelling or shrinking. This change in cell shape leads to the rapid movement of the plant's leaves folding and drooping.

Thus, the stimulus is touch, and the cause of the rapid movement is the electrical-chemical communication between cells leading to changes in cell shape, without any growth involved in this movement​.