Plant Hormones
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Transcript of Plant Hormones
Plant HormonesPlant Hormones
Plant growth regulatorsPlant growth regulators
What does a plant need to respond to in its
environment?
•Light•Water•Gravity
Positively phototrophicPositively geotrophic
Positively hydrotrophic
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.
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
How IAA works
Experiments
• What doe these prove?
• Page 160 has the final lot of experiments explaining the action of IAA
geotropism