Question

how do the plant respond to external stimulus?

Answer 1

Plants are known to respond to a number of external stimuli like light, gravity, touch, chemicals, etc. Plants respond to the external factors with the help of receptors and hormones. The receptors help the plants to sense the external stimulus and act accordingly. As a result of these stimuli, various growth hormones are produced which result in the movement or directed growth of the plant. For example: Auxins are one of the major plant hormones which regulate the growth of a plant. They control the growth of plant in response to light.

Answer 2

Plants are known to respond to a number of external stimuli like light, gravity, touch, chemicals, etc. Plants respond to the external factors with the help of receptors and hormones. The receptors help the plants to sense the external stimulus and act accordingly. ... They control the growth of plant in response to light.