Question

What is stimuli in plants in biology?

Answer 1

Plants produce hormones and respond to external stimuli, growing towards sources of water and light, which they need to survive.

A tropism is a growth in response to a stimulus and an auxin is a plant hormone produced in the stem tips and roots, which controls the direction of growth. Plant hormones are used in weed killers, rooting powder and to control fruit ripening.

Sensitivity in plants

Plants need light and water for photosynthesis. Plant responses - called tropisms - help make sure that any growth is towards sources of light and water.

There are two main types of tropism:

positive tropism – the plant grows towards the stimulusnegative tropism – the plant grows away from the stimulus.

Phototropism is a tropism where light is the stimulus. A gravitropism (also called a 'geotropism') is a tropism where gravity is the stimulus. The roots and shoots of a plant respond differently to the same stimuli.

Answer 2

Explanation:

In physiology, a stimulus is a detectable change in the physical or chemical structure of an organism's internal or external environment. The ability of an organism or organ to detect external stimuli, so that an appropriate reaction can be made, is called sensitivity.