Question

What do u mean by thigmotropism

Answer 1

from wiki

Thigmotropism is a directional growth movement of curvature which occurs in response to stimulus of contact. Thigmotropism is found in twining plants and tendrils. After initial contact with support due to nutation, the tendril or twiner shows less growth in the region of contact and more growth on the opposite side. As a result, they bend around the support. Later on, bending or coiling may occur in untouched parts of the tendril as well. Thigmotropism is a movement in which a plant moves or grows in response to touch or contact stimuli. The prefix thigmo-comes from the Greek for "touch" (θιγμός). Usually thigmotropism occurs when plantsgrow around a surface, such as a wall, pot, ortrellis. Touched cells produce auxin and transport it to untouched cells. Some untouched cells will then elongate faster socell growth bends around the object.

Roots also rely on touch to navigate their way through the soil. Generally, roots have a negative touch response, meaning when they feel an object, they would grow away from the object. This allows the roots to go through the soil with minimum resistance. Because of this behavior, roots are said to be negatively thigmotropic. Thigmotropism seems to be able to override the strong gravitropicresponse of even primary roots. Charles Darwin performed experiments where he found that in a vertical bean root, a contact stimulus could divert the root away from the vertical.[citation needed]

Other kinds of tropisms include gravitropism,phototropism, hydrotropism, andheliotropism. Gravitropism is the principle of turning based on gravity. Phototropism is the principle of turning based on the source of the plant's light. Hydrotropism is when the plant's roots grows toward a source of water. Heliotropism is when a plant follows the sun throughout the day. The helianthus (sunflower) is a plant that uses heliotropism.

Answer 2

Thigmotropism is the directional response of a plant organ to touch or physical contact with a solid object. This directional response is generally caused by the induction of some pattern of differential growth. This phenomenon is clearly illustrated by the climbing tendrils of some plants, such as the sweet pea.