Plant Growth Responses F215 Flashcards
(19 cards)
Plants need to respond to the environment because:
They cannot move–> need to respond to adverse conditions to survive (abiotic and biotic stress)
Control plant growth for the best possible conditions (roots, shoots, stomata)
Geotropism
Gravity.
Roots positive geotropism- towards gravity
Shoots negative geotropism- away from gravity
Phototropism
Light.
Shoots positive phototropism- towards light
Chemotropism
Chemicals (water)
Pollen tubes grow towards chemicals directing to the ovary
Thigotropism
Winding around a structure, as seen in climbing plants
Nastic responses are (4)
faster
not hormone controlled
temporary
due to cell turgidity
Plant Hormones:
Made in many different plant tissues
Animal Hormones:
Made only in endocrine glands
Plant Hormones:
Move by active transport, diffusion, mass flow
Animal Hormones:
Move in the blood
Plant Hormones:
Can act at production site or affect most cells in the plant
Animal Hormones:
Only act on target organs
Plant Hormones:
Have different effects depending on cell/plant/time of year
Animal Hormones:
Same constant effect
Plant Hormones:
Present in small quantities
Animal Hormones:
Present in large quantities
Plant Hormones:
Can work antagonistically or synergistically
Animal Hormones:
Can only work antagonistically
Plant Hormones:
Response tends to be slower
Animal Hormones:
Response tends to be faster
Plant Hormones:
Binds with cell surface plasma membrane, initiating response
Animal Hormones:
Binds with cell surface plasma membrane, initiating response
Auxins
Promote cell elongation
Inhibits side shoot growth
Inhibits leaf abscission
Cytokinins
Promotes cell division
Gibberellins
Promotes seed germination and stem growth
Abscisic acid
Inhibits seed germination and growth
Causes stomata to lose when water is unavailable
Ethene
Promotes fruit ripening
