Question

Closure of lamina in venus fly trap ( Dionaea muscipula) after an insect happens to alight over it is
A. Thigmotropism
B. Haptonasty
C. Chemotropism
D. Chemonasty

Answer 1

Hint: The venus fly trap comes under carnivorous plants found in subtropical wetlands (North Carolina and South Carolina). It found insects with a trapping structure formed by the ending portion of each of the plant's leaves, which is initiated by tiny hairs on their inner surfaces.

Complete Answer:
- Haptonasti or thigmonasty is defiend as the non-directional movement of plants when their parts are in contact with any object.
- When an insect comes in contact with Venus fly trap then it’s lamina is closed which is the type of haptonasti. If insects try to cross the lamina then the leaf will also close to prevent the immediate escape of inscet.
- The opposite of the thigmonasty is the directional growth movement of a plant when came in contact with an object is called thigmotropism.
- The parts which are climbing like tendrils try to reach to any kind of support and wind towards the support when came to connect with the object.
- Chemotropism is defined as the movements occur in the plant due to chemicals. Example growth of pollen tube towards the ovule in the process of fertilization.

So, correct answer is Haptonasti.

Note: Tiny hairs also known as "trigger hairs" or "sensitive hairs.
- Haptonasty also causes the rush of chemicals in the plant body.
- The non-directional movement of a plant because of chemical stimulus is understood as chemonasty. The changes are growth by movement in ions is an example of chemonasty.