Carbon Balance of Plants 01/ 18 Flashcards
What does photosynthesis do in an ecosystem?
Transducer of solar energy into chemical energy. The chemical energy drives the dynamics of both terrestrial and aquatic ecosystems.
What is the fundamental trade off for plants?
If they open their stomates to fix co2 from the atmosphere they lose water.
Simple model for plants (CO2) (input->storage->output)
Input- solar energy & fixed co2
Storage- plant biomass
Output- return of co2 into the atmosphere through cellular respiration.
What are the two dominant forms of photosynthesis?
C3 and C4
What are C4 plants & what does it mean to be a C4 plant?
grasses and they have c4 metabolism. The first product of photosynthesis is a 4 carbon organic acid.
What is a C3 plant & what doe it mean to be a C3 Plant?
Grasses, forms, trees, woody plants
Has a C3 metabolism in which the first product of photosynthesis is a 3 carbon organic acid.
What is CO2 compensation point?
Where respiration in the leaf equals gross photosynthesis
What is the compensation point for C4 plants?
Low- because C4 metabolism is much more efficient at scouring CO2 out of the atmosphere than C3 photosynthesis.
Where are C4 plants and C3 plants good competitors?
C4- desserts and dry grasslands (we find them in deserts in the southwest of the U.S)
C3- everywhere else
why don’t C4 plants rule the world if they have maximum rates of photosynthesis and are more water efficient?
Because there are ecological trade off’s having to do with their photo
Synthetic pathways.
-C3 plants have higher rates of net photosynthesis so this
Fundamental attribute of photosynthetic pathways influences the geo
Graphic distribution of a plants location (place)
-C4 pathways have evolved several times in plant evolution it enables
Plants to be good competitors where the environment is dry and hot.
Why don’t C3 plants rule the world if they have a higher photosynthetic capacity? or plant intolerant of shade
Higher photosyntheticapacity translate to higher rates of growth,
But require high rates of biochemical maintenance to continue
Running which is a disadvantage in shady enevironments.
What is Dark Respiration?
if I’m measuring photosynthesis & turn out the light
The plant is repirering
It’s taking the products of photosynthesis in using them to generate energy
To either build new tissue or maintain existing tissues & in the leaf.
What are the effects of temperature on Gross Photosynthesis?
Gross photosynthesis increases at a much faster rate as a function of temp
Than does respiration. Which causes a net carbon gain of a plant to increase.
Why does Gross photosynthesis decline as temperature gets hotter?
There is protein damage as temperature increases
Rubisco(enzyme that fixex co2) (most abundant protein in the world) denatures
It loses functionality
Temperature compensation point the carbon balance of the leaf is zero
Its fixing the same amount of co2 and gross photosynthesis as its
losing in respiration-negative carbon gain
Its burning reserves of carbohydrates just to stay alive.
Increased temperatures in plants causes respiration and altering the carbon balance of individual plants and their leaves.
