18 Flashcards
In the winter when deciduous trees loose their leaves, the net CO2 of the plant is?
Negative
Why does more CO2 increase photosynthetic efficiency in C3 plants?
Because of the competition between Calvin cycle and photorespiration by rubisco.
Rubisco evolved when life was?
Anaerobic
If CO2 increase, rubisco increase/decrease since?
Decrease, rubisco gets more efficient and it being composed of nitrogen, the plant synthesis less rubisco, and it requires less nitrogen.
!!!Increased CO2 increase/decrease stomatal conductance and increases transpiration efficiency?
Decrease since
Which type of plants benefit with an increase in CO2 concentration: C3, C4, & CAM?
C3
Increase C fixation by Rubisco results in? 3•
•Increased nitrogen use efficiency
•Increased water use efficiency
•Stronger effects on C3 plants which lack a carbon concentrating mechanism
Why would root length increase of CO2 concentration increase? 2•
•Stem length increase, which means that more nutrients is needed
•Roots act as sinks (storage) and if huge leafs are photosynthesizing a lot, then there is more opportunity to store.
What type of acid is present in acid rain?
When carbonic acid forms in the atmosphere
Since the beginning of the Industrial Revolution (~200 years ago), human activity have increased atmospheric CO2 levels by?
150%
Even though plants fix more CO2 than they produce and that humans produce, why is atmospheric CO2 increasing?
Because plants also produce CO2, and we cannot take atmospheric CO2, so we are causing an imbalance.
High temperatures and drier climates increase transpiration, and increase/decrease rubisco activity?
Decrease
!!!Why does an increase in transpiration decrease rubisco activity?
How does higher CO2 levels reduce water loss and decrease transpiration?
Stomata does not need to be open as much, so they can close them a bit more, which increase photosynthetic efficiency due to the increase of CO2, but reduce water loss and transpiration.
!!!Does climate change increase/decrease humidity?
