Photosynthesis of a tree canopy is driven or influenced by
air temperature (T).
photosynthetically active solar radiation (PAR).
soil moisture (REW).
air humidity (VPD).
the total leaf area (LAI).
To transform atmospheric CO2 into organic molecules, plants can use the energy from
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
The rate of respiration decreases with temperature.
Photoinhibition means the decrease in photosynthesis due to
exposure to high temperature.
exposure to excess of light.
exposure to shortage of soil moisture.
exposure to excess of CO2.
In some part of the stems, some photosynthesis may also occur.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
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.
Transpiration decreases as air becomes drier.
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.