Photosynthesis of a tree canopy is driven or influenced by
soil moisture (REW).
air temperature (T).
photosynthetically active solar radiation (PAR).
the total leaf area (LAI).
air humidity (VPD).
Transpiration decreases as air becomes drier.
In some part of the stems, some photosynthesis may also occur.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
Almost half of the total biomass of a tree may be allocated to the roots.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
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.
What is the source of carbon that is assimilated in photosynthesis?
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
The annual cycle of photosynthesis mainly follows
the changes in CO2 concentration.
the changes in air temperature.
the changes in soil temperature.
the changes in light.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
As plants respire, they release
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.