Question

Thigmotropism is best exhibited by
A) Lamina
B) Tendrils
C) Root apex
D) Thorns

Answer 1

Thigmotropism is a process seen in plants. Here we will discuss all about thigmotropism – what is it, how does it occur, what are its consequences.

Complete answer:
Thigmotropism:

Thigmotropism is also called haptotropism.Thigmotropism is the process in which a plant organ bidirectionally responds to touch or physical contact.
The factor that can change the direction of plant’s growth is generally a hard surface.
Thigmotropism can be in the form of coiling of plants around the surface, opening and closing of parts of the plants such as petals and sepals.
This process is typically found in tendrils and twining plants but it can also be seen in flowering plants and fungi.
The part of tendril that is in touch with the surface will produce a hormone called auxin and ethylene.
Types of Thigmotropism:
There are two types of thigmotropism:-
Differential growth
Rapid Contact coiling
Differential growth:-
In differential growth, one side of the plant grows faster than the rest of the plant upon stimulation.This growth can occur within minutes and is usually long lasting.
Rapid contact coiling:-
On the other hand, rapid contact coiling is an instant response.It does not last long lasting and happens quickly.Example – folding of leaves of some plant species when touched.
Hence, in the above discussion we have seen that the thigmotropism is best exhibited by tendrils.
So, option B is the right option.

Note: A tendril is a very thin thread like structure found in climbing parts and used for support. Tendril is a modified stem, petiole and leaf.