Question

What are tropic movement ? Given one example of each.

Answer 1

Tropic movement is the movement of the plant in response to the stimulus present in the environment, this movement is in response to root and shoot growth. They are mainly of five types:

1. Phototropism - It is the movement of a plant in response to light, they will grow towards the direction of the light. It may be positive (if towards the light) or negative phototropic (if away from the light).
2. Geotropism - The movement of the plant in response to the gravity, they will move in the direction of gravity. The roots will grow downwards and show positive geotropism while shoot will grow upwards and thus show negative geotropism.
3. Chemotropism - In seed plants, the movement of pollen grains to the female gamete is due to the secretion of chemicals. This shows positive chemotropism.
4. Hydrotropism - It is the movement of plants in response to water, the roots of the plant will grow towards the area where water is present.
5. Thigmotropism - It is the movement or action of reflex of a plant in response to the touch. It is commonly observed in the touch me not plant. As the leaves are touched they droop.