Question

Describe the responses found in organisms against the environmental abiotic factors. (Any three)

Answer 1

There are many different types of responses and movements shown by the plant against the environmental abiotic factors.

A response of a plant, that causes movement independent of the direction of the stimulus is a nastic response. It is not a growth response, is reversible, and can be repeated many times. Thermonasty is the type of nastic movement in response to a temperature change, as occurs in the opening of certain flowers.

Nyctinasty is the circadian rhythmic nastic movement of higher plants in response to the onset of darkness. For examples are the closing of the petals of a flower at dusk and the sleep movements of the leaves of many legumes.

Seismonasty is a nastic movement in response to shock, especially the rapid folding of the leaflets of the sensitive plant due to changes in turgor pressure, caused by vibration, example- Mimosa pudica.

Phototaxis is the response of a plant organ to the stimulus of light. This is shown by movement of plant towards sunlight.