PLANT MOVEMENTS • Plant shows various types of movements. Movements in plants are of two main types.They are
• 1) TROPIC
MOVEMENTS
• 2)NASTIC
MOVEMENTS
TROPIC MOVEMENTS • Tropic movements are directional movements towards ar away from stimulus.Tropic moements in plants are; • 1)Phototropism • 2)Geotropism • 3)Hydrotropism • 4)chemotropism • 5)Thigmotropism
1.PHOTOTROPISM • Phototropism is the movement of plants in response to light. • If movement towards light, it is called positive phototropism. Eg: bending of shoot towards light. • If movement is against light, it is called negative phototropism. Eg: bending of root away from light
NEGATIVE PHOTOTROPISM
MECHANISM OF PHOTOTROPISM
PHOTOTROPIC MOVEMENTS IN PLANTS
2.GEOTROPISM • It is the movement of plants in response to gravity. • If movement is towards the gravity Is called positive geotropism. Eg: downward growth of root.
• If movement is away from the gravity Is called negative geotropism. Eg: Upward growth of shoot
GEOTROPIC MOVEMENTS
POSITIVE AND NEGATIVE GEOTROPIC MOVEMENTS
GEOTROPIC MOVEMENTS IN PLANTS
3. HYDROTROPISM • Hydrotropism is the movement of plants in response to water. • If plant roots always move towards the water hence show positive Hydrotropism. • The growth of plant shoot the direction of water in the soil is an example of negative Hydrotropism.
HYDROTROPIC MOVEMENTS
HYDROTROPISM
4.CHEMOTROPISM • It is the movement of plants in response to chemical stimuli
• Growth of pollen tube towards ovule is an example for chemotropism.
CHEMOTROPISM
CHEMOTROPIC MOVEMENTS
5.THIGMOTROPISM • Thigmotropism is the directional movement, shown by parts of plants in response to touch or physical contact with other objects.
• Thigmotropism is typically found in twinning plants and tendrils, however plant biologists have also found thigmotropic responses in flowering plants and fungi.
THIGMOTROPC MOVEMENTS
NASTIC MOVEMENTS • Nastic movements are non directional movements that are not affected by direction of stimuli.
• Eg: If we touch the leaf of Mimosa or ‘ touch me not plant ‘its leaves fold up and droops down immediately due to change in the amount of the water in the leaves.