Question

Give scientific reasons. Roots of plants grow away from light.

Answer 1

Hint: The roots are the part of the plant which grows towards the gravity and the shoot away from the gravity. The movement of the plant in response to the stimuli is known as tropic movement. These movements are mainly responsible for the growth.

Complete answer:
The growth movement of the plant in response to the stimulus is known as tropic movement. These movements help the plant to adapt better with their surroundings. The growth movement is typically shown by the roots and stem.
The stem of the plants move towards the sunlight. This movement is called phototropism. Whereas the roots are negatively phototropic but positive geotropic. This is the reason why the roots move away from the light. The stem is adapted for showing response or growth movement towards light and the root shows the growth movement towards the gravity that is towards the centre of the earth.

The other types of tropic movements are:
Phototropism-The growth movement in response to light.
Chemotropism- The growth movement in response to particular substances or chemicals.
Hydrotropism- The growth movement in response to water.
Thigmotropism- The growth movement in response to mechanical stimulation.
Traumatropism- The growth movement in response to wound lesion.
Galvanotropism or electrotropism- The growth movement in response to electric current.

Note: The other movements exhibited by plants are nastic movement and tactic movement. The nastic movement is exhibited by mimosa. The nastic movement is not a growth movement. It is only exhibited in response to stimuli but not for growth. The tactic movement is for locomotion but is unidirectional.