Photosynthesis of a tree canopy is driven or influenced by
air temperature (T).
air humidity (VPD).
the total leaf area (LAI).
soil moisture (REW).
photosynthetically active solar radiation (PAR).
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.
In some part of the stems, some photosynthesis may also occur.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
Transpiration decreases as air becomes drier.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
The annual cycle of photosynthesis mainly follows
the changes in CO2 concentration.
the changes in air temperature.
the changes in light.
the changes in soil temperature.
The rate of respiration decreases with temperature.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
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.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
As plants respire, they release
Photosynthesis releases oxygen whereas respiration releases CO2.