Question

Movement of Mimosa pudica (sensitive plant) leaves is due to
A)Nerve impulse
B)Delicate leaves
C)Loss of tissue
D)Turgor change in leaf base

Answer 1

Hint: 1)Mimosa pudica exhibits touch-induced movement.
2)The leaves of the plant droops upon touching, shaking,wind etc.

Complete answer:
Mimosa pudica is an annual flowering plant which exhibits stimuli-induced where the leaves fold up and return to full leaf in a few minutes. This is a defence mechanism

Option A: Nerve impulse is a way of communication among the nerve cells. Although plants do not have nerves they can produce action potentials which basically occurs due to accumulation of ions on the cell membrane and their concentration difference. As this is not the case for Mimosa pudica, This is an incorrect option.

Option B: Movement in Mimosa pudica is not due to delicate leaves. So this is an incorrect option.

Option C:There is no loss of tissue when a Mimosa plant is being touched or given a stimuli. Hence this is an incorrect option.

Option D:When a Mimosa pudica plant is being touched, the leaves react to the stimuli as there is higher pressure at that point and vacuoles of the cells lose water to the adjacent cells and the leaf becomes flaccid. I.e, loss of turgor pressure occurs. Therefore, this is the correct option.

The capability to exhibit touch-induces movement is called Thigmonasty. The speed of the response depends on the magnitude of the stimulus. Also the stimuli here is external.
This plant is also called ‘sleepy plant’ or ‘humble plant’ or ‘shy plant’.

Hence, the correct answer is option (D)

Note: Nerve impulse in plants, i.e action potential should not be misunderstood as the reason for movement in Mimosa pudica, as it occurs due to difference in ion concentration in cells. In Mimosa pudica it is due to an external stimuli and is dependent on pressure difference.