CAM Flashcards
What conditions are CAM plants well adapted to
Dry areas
How do CAM plants temporally separate carbon fixation and rubisco
Open stomata at night only and convert CO2 to malate and stored in vacuole
During day malate is converted back and enters CBB cycle as CO2
What enzyme fixes CO2 into malate
PEP carboxylase
Why is CAM less efficient than C4
CAM plants are inactive during day
When would a plant carry out facultative CAM
When under stress e.g. drought, salt, high light intensity
Why are CAM plants more water efficient than C3 or C4
Because stomata are closed during day to prevent water loss
What are 6 adaptations to low water
1, succulence - water storage
2, reduced leaves - reduced surface area
3, compact growth form - low surface area for low water loss
4, ribs - allows plants to swell in times of high water supply
5, thick cuticle - prevents water loss and increase of water tension
6, surface roots - allow rapid absorption of water
What are 5 leaf adaptations to low water environments
1, thick cuticle - low permeability
- Stomata open and close variably
- Trichomes or spines increase thickness of boundary layer
- Sunken stomata preventing air from reaching surface
- Rolled leaves - protect stomata from air movement
When guard cells are flaccid stomatal pores are
Closed
What ion movement causes opening of guard cells
H+ ions out and K+ ions in
Thus lowers water potential in guard cells and so water moves in
What type of light is more effective at stimulating opening of guard cells
Blue light - red is least effective
What are water levels signalled by in plants
The roots
