1. Plant Hormones Plant growth regulators

2. What does a plant need to respond to in its environment? Light Water Gravity Positively phototrophic Positively geotrophic Positively hydrotrophic

3. How are plant growth factors different from animal hormones? They exert an influence by affecting growth Produced and released by cells through out the plant rather than organs. They affect the tissues or nearby tissues that release them, not distant target organs.

4. Examples Auxin – effects growth of the plant – example = IAA (the one you need to know about. Cytokinins - growth control in fruit Ethylene - promote ripening on the tree Gibberellins – promote seed germination

5. How IAA works

6. Experiments What doe these prove?

7. Page 160 has the final lot of experiments explaining the action of IAA

9. geotropism