Question

 What is the difference between thigmotropism and thigmonasty? Name one plant which exhibits thigmotropism and one plant which exhibits thigmonasty. What behaviour (or responses) of these plants make you think that they exhibit thigmotropism and thigmonasty respectively?

Answer 1

Thigmotropism	Thigmonasty
It is a  directional movement of plant parts in response to touch.	It is a non-directional movement of plant parts in response to touch.
Example: Bitter gourd	Example: Mimosa pudica

Bitter gourd exhibits thigmotropism as its tendrils show directional movement towards the things they happen to touch.
On the other hand, Mimosa pudica exhibits thigmonasty as its leaflets show non-directional movement in response to touch.