Question
Describe with examples the different types of movements which are observed in plants.
Answer
Movement: The process by which the living organism remains fixed in a place but its parts or organs show a change of position due to the influence of stimuli, is known as movement.
Types of plant movement: Plant movements are classified into three categories: Tactic, Tropic and Nastic.
- Tactic movement: The movement of locomotion induced by external stimuli like temperature, light, chemicals etc., is called tactic movement. Example – Chlamydomonas
- Tropic movement: When the direction of growth movement of curvature of a plant organ bears a definite relation to the direction of stimulus (either towards or away from the stimulus), then the movement is termed as a tropic movement. Example – Root and shoot of the plant.
- Nastlc movement: The movement of curvature of a plant organ that bears no relation to the direction of the stimulus but Is responsive to the intensity of the stimulus, Is called nastic movement. Example – Photonastic movement in Sunflower.
