Question

Tendrils and twiners come in contact with their support by means of
a. Nutation
b. Thigmonasty
c. Thigmotropism
d. Anemotropism

Answer 1

Hint: Tendril, a plant organ specializing in anchoring and protecting vine stems in botany. Modified leaves, leaflets, leaf tips, or leaf stipules may be tendrils, but they may be derived from modified stem branches. Some special plant structures serve a similar function, but the tendril is unusual in being a specialised lateral organ with a powerful twining propensity that causes any entity encountered to be surrounded by it.

Complete answer:
> Nutation- Nutation refers to the bending motions of the stems, roots, leaves and other organs of the plant that are caused by growth variations in the various parts of the organ. Nutational movements are normally distinct from variational movements triggered by temporary changes in water pressure within plant cells.

> Thigmonasty- Thigmonasty or seismonasty is the nastic response to touch or vibration of a plant or fungus. Many species in the leguminous subfamily Mimosoideae, active carnivorous plants such as Dionaea, and a wide variety of pollination mechanisms provide conspicuous examples of thigmonasty.

> Thigmotropism- Thigmotropism is a plant organ's lateral reaction to touch or physical contact with a solid material. This directional response is generally induced by the induction of some pattern of differential development. An example of thigmotropism is the curvature motions due to support seen in tendrils and twiners. The climbing tendrils of certain plants, such as sweet peas, clearly demonstrate this phenomenon.

> Anemotropism- The orientation of plants in reaction to the direction of the wind. The basidiocarps exhibited anemotropism while growing in the wind tunnel. Anemotropism plays an important role in the ease of the ladybirds in regulating the course of their movements, to which they respond negatively.

Hence, the correct answer is option (C).

Note: Tendrils have no lamina or razor, but they are capable of photosynthesizing. It is only the terminal leaflets of the garden pea that are changed to become tendrils. The entire leaf is adapted to become tendrils in other plants, such as the yellow vetch, while the stipules are expanded and photosynthesized.