Give examples to show how plants respond to stimuli.
Plants respond to various stimuli. Response to environmental stimuli is known as tropism and the stimuli may be light, water, gravity, etc. Various types of tropism are:- Phototropism: Movement or growth of plants towards light is called phototropism. For example, sunflower turning towards the sun.
- Hydrotropism: Plant roots grow deeper into the soil in response to higher water concentration.
- Chemotropism: It refers to the movement of plant or plant parts towards a specific chemical or hormone. For example, pollen on stigma grown pollen tubes towards the ovules.
- Geotropism: Geotropism is the response of plants towards gravity. Positive geotropism is observed when roots are seen growing down.
Apart from tropism, plants also respond to touch; for instance, closing of leaves of
Mimosa (touch me not) plant when someone touches them. Tendrils that help in growth and support of plants also are responsive to touch.