Question

When the leaf of the 'touch-me-not'(chui-mui, Mimosa pudica) plant is touched, the leaf drops because.

• A. A nerve signal passes through the plant
• B. The temperature of the plant increases
• C. Water is lost from the cells at the base of the leaf
• D. The plant dies

Answer 1

Answer: (C)

Water is lost from the cells at the base of the leaf

• The Mimosa plant folds the leaflets on stimulus with touch. The stimulus is passed on to the entire branch and then the whole plant with all the leaflets close.
• There is a loss of water from the cells at the base of the leaf.
• This is due to the passing of the impulse which causes a change in the turgor pressure in the cells causing the leaflets to be closed.

Thus, the correct answer is option C.