Question

Describe any two tropic movements with examples of each.

Answer 1

Tropic movements

1. Tropic movements are gradual directional responses shown by a plant in response to an external stimulus.
2. Various stimuli like light, gravity, water, chemicals, objects, and temperature stimulate the plant to exhibit tropic movements. They can be either positive, towards the stimulus, or negative, away from the stimulus.

Examples of tropic movements

1. Thigmotropism, a curvature movement, occurs due to the presence of an object that modifies the growth orientation in a plant. It is seen in plants with weak stems like Grapevine and Cucurbita. The tendrils of the plant wrap around the object thereby helping the weak stem climb up.
2. Thermotropism, a curvature movement, occurs in response to temperature. This can be seen in the leaves of Rhododendron leaves which curl when the temperature is cold.