NEET BIOLOGY

Detailed explanation-1: -In Greek, the prefix “thigmo-” refers to the touch stimuli and the suffix “-nasty” denotes the nastic movement; thus, the term “thigmonasty” indicates the coiling or curling up movement of plant structures when they are touched.

Detailed explanation-2: -The growth movement of plants in response to the stimulus of touch is called thigmotropism. Thus, the stimulus for thigmotropism is “Touch”.

Detailed explanation-3: -Thigmonasty movement: The non-directional movement of a plant in response to the contact of an object is called Thigmonasty movement. In the insectivorous plant’s leaves like Drosera, Dionaea the tentacles show variation in movements on coming in contact with an insect.

Detailed explanation-4: -Thigmonasty or seismonasty is the nastic response of a plant or fungus to touch, heat or vibration. It differs from thigmotropism in that it is independent of the direction of the stimulus. For example, the growth of roots through soil is thigmotropic because the roots grow away from rocks.

Detailed explanation-5: -The stimulus which is attained by the plant can be in the form of biological, electric, chemical, touch, compression, temperature, etc. Mechanical stimulation like touch or contact, rapid winds, raindrops, etc. cause seismonastic movement in plants.