Lecture 5 - CAM Flashcards
CAM you dig it/?? A relaly good film , I'd recommend waching hte warriors tbh
What is CAM?
Crassalucean Acid Metabolism
Where are CAM plants frequent?
CAM is frequent in areas which are very dry and either have simply very low rainfall or varied, fluctuating rainfall.
What is a bromeliad?
A bromeliad is a pineapple.
What’s Tillandsia usenoides
Tillandsia usenoides is a Spanish moss.
What is an epiphyte?
An epiphyte lives on other plants, so its roots dry out quick.
Where are ‘desert’ microclimates in rainforests?
The rainforest canopy, as it is direct view of sunlight can act as a ‘microclimate’.
What does a lack of water lead to in plants?
A lack of water in plants leads to increased photorespiration.
What temperature and humidity are characteristic of desert regions.
30C + degrees and 60% humidity are characteristic of desert regions.
60% humidity is a relatively low humidity.
30c+ degrees and 60% humidity (quite low apparently)
What is the primary adaptation of CAM beneficial for?
CAM is beneficial especially in fluctuating water systems.
What % of angiosperm species are CAM plants?
7% of Angiosperms are CAM plants.
What is CAM associated with?
CAM is associated with succulent plants, water conservation and lots of cells in tissues.
A ‘squishy’ plant is often a CAM plant.
What is CAM in terms of C mechanisms
CAM plants have a temporal separation of the Calvin Cycle and Carbon fixation.
This simply means different reactions happen at different times of the day.
Fixation occurs at night.
When are stomata open in CAM
During night, so low water loss while carrying out C fixation. In day they close stomata to avoid losing water.
What happens when day comes for CAM plants?
Stoamta closed and Calvin Cycle continues during the day.
Explain process of CO2 in CAM
Converted to HCO3- ions, then thats used to convert C3->C4 (cata by pep carboxy) usually malate
What happens to malate
Moved into vacuole, stored throughout night and gets high levels, returns to C3 i nday via co2 release where it can be used in calvin cycle. Hence spatial separation where plant cna do photosynth during the day when stomata closed
What happens in CO2 fixiation in sugars IN CAM?
CO2 fixation goes up overnight, and is low during the day.
What happens to malate levels during a day?
Increases during day, decreases at night
Why isn’t CAM so efficient?
Since doesn’t photosynthesise during the day.
What’s faculative CAM?
Photosynthesis can turn on/off during day, can work in high-water periods normally and swap to CAM when dry (thank you acclimiation)
name 3 faccy cam plants
Mesmbryantheum crystallinum (icey plant) Talinum triangulare (Suriname purslane), Clusia minor
When may faculative CAM occur?
Faculative CAM can occur in ares which may mimic low-water environments.
Salt stress, other deficiencies etc.
How do we know Surinmae purslane does this?
We know this, since in water-stressed environments the Suriname purslane makes more malate. A sign of faculative CAM.
How many tissues in Clusia minor respond to stress
8 tissues respond differently to different stress
What’s aquatic CAM?
Aquatic CAM adaptations happen due to low CO2 availability… rather than water.
happens in aq
How much slower is CO2 diffusion in water?
CO2 diffusion in water is 10,000x slower. It’s even worse in low pH water.
Explain CAM in terms of water-use efficiency
CAM helps with how efficient a plant is at using water to produce biomass.
Water use efficiency = CO2 taken up vs water lost
How much air needed to manufacture 1g of sucrose?
5kL of air is required.
Whats water use effifency of CAM plants?
like 0.0164-0.0165
Whats CO2 uptake of CAM
This varies between plants. It’s .32 in Agave desertii, and .2828 in Ferocactus acanthodes
What about H2O loss in CAM
26 in Agave desertii, 17 in Ferocactus acanthodes
Whats CO2 uptake in C3 and C4 plants respectively
1.02 and 1.26
Way higher than CAM. Also H2O loss is way higher.
Whats water use efficency in C3 and C4 plantys
0.0009 and 0.0017, far lower than in CAM.
How do you calculate water-use efficiency?
CO2/H2O
How much more efficient is CAM at water conservation than C3 and C4?
CAM is like x10 more efficient.
Whats drawback of CAM plants
CAM plants have very little uptake and so reactions are slower.
Order of efficency of water usage in c3,c4 and CAM?
C3 plants are the least efficient. CAM are the most.
This is down to when stomata are open.
What’s succulence?
Succulence refers to filling the leaves with as much water as possible.
Whats the point in reducing the leaves in dry plants?
If there’s lots of light, big leaves may not be needed and the plant can absorb enough sunlight through the stems. This reduces the amount of stomata and hence reduces water loss.
What adaptation is a compact growth form?
A compact growth form can help reduce surface area available for transpriation and impacts of wind.
What are ribs an adaptation for?
Ribs are structure with areas of tissue between them, which can swell when water content is high and shrink when not.
What is a thick cuticle for?
Thick cuticles can help slow down transpiration.
What is the boundary layer of a plant?
A very thin layer of air existing around the leaf.
How can you increase the boundary layer of a plant?
Spines, leaf hairs, sunken stomata etc. this is done to reduce wind exposure and transpiration.
Or leaves may be rolled up.
What is cellulose useful for in guard cells?
Providing some structure and preventing them simply expanding.
Is blue or red light more effective in causing stomata to open?
Blue light is more effective
What does Abscisic acid do?
It’s a signalling hormone, which is responsible for signalling water levels in the soil to the leaves.
If added directly it can cause stomata to close. as plants ‘act ‘ stressed.
How do C4 and CAM plants differ in distribution?
While both are present in dry areas, CAM is present in EXTREMELY dry areas.
