Control & coordination IV
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This document discusses different types of tropisms in plants, which are growth movements in response to external stimuli. The main tropisms discussed are phototropism (movement towards light), geotropism (movement towards gravity), thigmotropism (movement in response to touch), hydrotropism (movement in response to water), and chemotropism (movement in response to chemicals). Each tropism causes either positive or negative movement towards or away from the stimulus. For example, shoots are positively phototropic and negatively geotropic, while roots display the opposite responses.
Control & coordination IV
- 1. CHEMICAL COORDINATION IN PLANTS
- 3. TROPIC MOVEMENTS IN PLANTS Phototropism Geotropism Thigmotropism Hydrotropism Chemotropism Growth Movements in response to an external stimulus.
- 4. TROPISM Tropism is a growth movement in response to a stimulus. Plants grow towards or away from stimuli. A growth movement towards a stimulus is called a positive tropism. A growth movement away from a stimulus is called a negative tropism.
- 5. Plant responses to stimuli are given specific names: What do the names of each tropism mean? ARE THERE DIFFERENT TYPES OF TROPISMS? Water GravityLight Touch Chemical
- 7. PHOTOTROPISM Phototropism is movement towards light What will happen when light is brighter on one side? Then the shoot will bend towards more light. Shoots are positively phototropic and roots are negatively phototropic
- 9. GEOTROPISM Geotropism is the movement of plant part towards earths gravity Shoots are negatively geotropic Roots are positively geotropic
- 10. How do plants always grow the right way up? Plants respond to gravity to grow in the right direction. Which way up?
- 13. THIGMOTROPISM Thigmotropism is the movement of plant part in response to touch • Sweet pea cuscuta and wines have tendrils which coil around the plants in response to touch. • Stimulus is perceived at the tip and is transmitted to the other parts
- 15. HYDROTROPISM Hydrotropism is the movement of plant part in response to water or moisture Roots are positively hydrotropic Shoots are negatively geotropic
- 16. HYDROTROPISM Experiment to prove roots are positively hydrotropic
- 17. EXPERIMENT
- 19. CHEMOTROPISM Chemotropism is the movement of plant part in response to Chemicals Movement of pollen tube towards sugar and peptones secreted by the female gamete
- 20. CHEMOTROPISM Movement of fungi towards the source of nutrition Movement of tentacles of insectivorous plants like, Drosera (sundew) towards the source of nutrition
- 21. HELIOTROPISM
- 22. THANK YOU