Question

Mimosa pudica (touch me not plant) shows
(A) Thigmotropism movement
(B) Chemotactic movement
(C) Seismonasty
(D) None of the above

Answer 1

Hint: These movements are caused by the mechanical stimulus, like contact with a far off body, fast wind, and raindrops, etc. It is often observed in stigmas, stamens, and leaves of many plants.

Complete solution:
‘Touch me not’ plant shows seismonastic movement. The ‘touch me not’ plant (Mimosa pudica) is documented for its rapid plant movement. It undergoes changes within the orientation of leaf termed "sleep" or nyctinastic movement. The foliage (leaves) closes during the darkness and reopens within the light. The leaves also close under other simulations also, like touching, warming, blowing, or shaking. These sorts of movements are thus termed seismonastic movements.
The movement occurs when the specific regions of cells lose turgor pressure, which is the force that is applied onto the cell wall by water within the cell vacuoles and other cell contents. When the plant is disturbed, the precise regions on the stems are stimulated to release chemicals including potassium ions. It forces water out of the cell vacuoles, the water diffuses out of the cells, producing a loss of cell pressure, and therefore the cell collapses. Thus, the difference in turgidity between different regions of cells leads to the closing of the leaflets and therefore the collapse of the leaf petiole. -Other plants, that are found in nature that show seismonastic movement, are Biophytum sensitivum and Neptunia oleracea.
-Smaller plants and naked protoplasmic bodies show movements of locomotion whereas the upper plants, being fixed during a position, show movements of their parts.

So, the correct answer is ‘Seismonasty’.

Note:
The extent of the seismonastic movement depends upon factors like the intensity of the stimulus, the vigor, and age of the plant, and therefore the time elapsed since the last stimulus. Touch me not plant is grown for its curiosity value as it shows this unique feature.