1. Plant Hormones and Responses

2. Environmental Factors
Etiolation
(absence of light)
Greening
(presence of light)

3. Signal Reception

4. More complicated ...

5. Hormones

6. Hormones

7. Early Experiments

8. Discovery of Auxin

9. Activity of Auxin

10. Gibberellins

11. Ethylene
Ceneraria leaves rolled in from the sides in response to exposure to ethylene

12. Normal
Ethylene
Less
Ethylene

13. Normal
Ethylene
Less
Ethylene

14. Ethylene & Senescence

15. Leaf Abscission
Protective
Layer
(suberized)
Petiole
Separation
Layer

16. Ethylene – Triple Response

17. Abscisic Acid & Stomata

18. Plant Tropisms

19. Phototropism

20. Gravitropism (aka geotropism)

21. Thigmotropism

22. Nastic Movements

23. Nastic Movements: Action Potentials?

24. Photoperiodism

25. Red Light Interuptions

26. Joined Plants