Plant Behaviours Flashcards
1
Q
Behaviour
A
-response to stimuli
2
Q
Taxis
A
-response to negative and positive stimuli in moving animals/plants
3
Q
Tropism
A
-a response to stimuli in sessile (stuck) plants and animals
4
Q
Phototropism
A
-responses to light, positive (towards) negative (away)
5
Q
photoreceptors
A
- blue light (causes auxin to dissipate, open stomata, responsible for phototropism)
- photochromes
6
Q
Blue Light
A
- Cryptochromes: inhibition of elongation of hypocotyl
- Phototropin: phototrophic response, opens stomata
- Zeaxanthin
7
Q
Red light
A
- phytochromes: found in all vascular plants
- Pr: absorbs red light at 660nm
- Pfr: absorbs red light at 730nm
- exposure will switch between the two
- responsible for circadian rhythm
8
Q
Photoperiodism
A
- short day plants: minimum critical night length, Pfr inhibits flowering
- long day plants: maximum critical night length, Pfr induces flowering
- neutral day plants: tropic plants, no change in day cycle
9
Q
Gravitropism
A
- response to gravity
- positive gravitropism: roots grow with gravity
- negative gravitropism: shoot grows away from gravity ^
10
Q
Thigmomorphogenesis (mechanical stress)
A
- a response in which plants grow stockier and shorter
- positive mechanical stress: grows towards obstacles
- negative: grows away from obstacle
- Tactile Stimuli: i.e sensitive mimosa
11
Q
Drought
A
- stomata close
- produces abscisic acid
- leaves droop
- inhibits young leaf growth and shallow roots
12
Q
Flooding
A
-low O2 causes release of ethylene -> apoptosis
13
Q
Heat
A
- evaporative cooling
- heat shock proteins
14
Q
Cold
A
- alters lipids (addition of saturated fatty acids)
- increases concentration of sugar (starches/increases freezing point)
- water in cells freeze
15
Q
Cold
A
- alters lipids (addition of saturated fatty acids)
- increases concentration of sugar (starches/increases freezing point)
- water in cells freeze
