Question

Give biological reasons for the following:
Tendrils are positively thigmotropic.

Answer 1

Thigmotropism is the movement or change in orientation of a plant’s growth as a reaction to touch. The orienting factor is generally a hard surface that can change the direction of the plant’s growth or the growth of one of its organs.

A tendril is a slender whiplike or threadlike strand, produced usually from the node of a stem, by which a plant may climb. It is a modified leaf, stem, or petiole, that possesses coiling as its form of thigmotropism.

Tendrils start bending in search of a surface to grow across. Once they find it, the part of the tendril that is in touch with the surface will bend and coiled around to get the support.

This is the reason tendrils are positively thigmotropic.