Question
What is nastic movement in plants? Mention three types of nastic movement in plants.
Answer
Nastic movement is a type of plant movement that is independent of the direction of the stimulus. In other words, the direction of the response is not dependent on the direction of the stimulus, unlike tropic movements. Instead, nastic movements occur due to changes in turgor pressure, which cause the plant to change its shape or position.
Here are three types of nastic movements in plants:
- Thermonasty: Thermonasty is the nastic movement of plants in response to changes in temperature. The movement is typically in response to a decrease in temperature, and the plant’s leaves or flowers close up to protect themselves from the cold. An example of a plant that exhibits thermonasty is the tulip flower.
- Nyctinasty: Nyctinasty is the nastic movement of plants in response to changes in light-dark cycles. The movement is usually in response to darkness, and the plant’s leaves or flowers close up. An example of a plant that exhibits nyctinasty is the mimosa pudica or “sensitive plant,” which folds its leaves in response to touch or darkness.
- Seismonasty: Seismonasty is the nastic movement of plants in response to mechanical stimuli such as touch or vibration. The movement is not directional, and the plant’s leaves or branches move in response to the stimulus. An example of a plant that exhibits seismonasty is the Venus Flytrap, which closes its leaves around insects when they trigger the plant’s sensitive hairs.
