|Class 10 Biology Control and Coordination||Coordination in plants|
Movement dependent on growth
Plants respond to stimuli by growing in a particular direction and because of the directional growth it appears as if the plant is moving.
Tropic movement or tropism is the plant movement that is determined by the direction of an environmental stimulus.
Tropic movements can be towards the stimulus or away from it.
The tropic movements are of various types depending on the nature of stimulus-
Fig. Roots grow towards gravity
Movement independent of growth
For eg. i) In sensitive plants, the plants move its leaves in response to touch
ii) The movement takes place at a point different from the point of touch.
iii) Some cells change shape by changing the amount of water in them and as a result the cells either shrink or swell and therefore change shapes.
Fig. sensitive plant