Question

What do you mean by seismonastic movement? Name the types of movements in plants.

Answer 1

Seismonastic movements:

1. The non-directional movement of a plant part in response to an external stimulus is known as a nastic movement.
2. The stimulus which is attained by the plant can be in the form of biological, electric, chemical, touch, compression, temperature, etc.
3. Mechanical stimulation like touch or contact, rapid winds, raindrops, etc. cause seismonastic movement in plants.
4. Many plant parts, including the stigmas, stamens, and leaves, exhibit seismonastic movements.
5. For example - The leaflets of the Mimosa pudica plant rapidly fold and droop in response to touch.

The different types of movements in the plants are:

1. Phototropism: It is an activity in the direction of the light; the plant moves towards the direction of sunlight. An example of a plant showing phototropism is Sunflower.
2. Hydrotropism: It is an activity in the direction of the water. This is the activity shown by roots close to the source of water. It is demonstrated by radish roots, tomato roots, etc.
3. Geotropism: It is the growth of the plant’s parts in response to gravity. For example, the roots of plants demonstrate geotropism.
4. Chemotropism: It is the growth of the parts of the plant in response to a chemical stimulus. The movement of the male gametes in the direction of the egg is chemotropism. For example, the elongation of pollen tubes and fertilization in flowering plants is chemotropism.