stimulus
Relay proteins and
second messengers
Activation
of cellular
responses
1
2
3
Slide 76
Review
Photoreversible states of phytochrome
Pr
Pfr
Red light
Far-red
light
Responses
Slide 77
You should now be able to:
Compare the growth of a plant in darkness (etiolation) to the characteristics of greening (de-etiolation).
List six classes of plant hormones and describe their major functions.
Describe the phenomenon of phytochrome photoreversibility and explain its role in light-induced germination of lettuce seeds.
Explain how light entrains biological clocks.
Slide 78
Distinguish between short-day, long-day, and day-neutral plants; explain why the names are misleading.
Distinguish between gravitropism, thigmotropism, and thigmomorphogenesis.
Describe the challenges posed by, and the responses of plants to, drought, flooding, salt stress, heat stress, and cold stress.