Transpiration decreases as air becomes drier.
What is the source of carbon that is assimilated in photosynthesis?
Leaf area increases with stand age, resulting in a decreasing rate of photosynthesis in the stand.
An increment in leaf area increases also the photosynthesis of a tree stand. However, the relationship is saturating.
Photoinhibition means the decrease in photosynthesis due to
exposure to high temperature.
exposure to excess of CO2.
exposure to shortage of soil moisture.
exposure to excess of light.
As plants respire, they release
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
The effect of light on photosynthesis has a clear saturating pattern: more light results in more photosynthesis but eventually leaves cannot take full advantage of all the extra light.
Photosynthesis of a tree canopy is driven or influenced by
air temperature (T).
the total leaf area (LAI).
soil moisture (REW).
air humidity (VPD).
photosynthetically active solar radiation (PAR).
The rate of respiration decreases with temperature.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
The annual cycle of photosynthesis mainly follows
the changes in air temperature.
the changes in soil temperature.
the changes in CO2 concentration.
the changes in light.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.