At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
Transpiration decreases as air becomes drier.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
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.
The rate of respiration decreases with temperature.
Photoinhibition means the decrease in photosynthesis due to
exposure to excess of CO2.
exposure to shortage of soil moisture.
exposure to excess of light.
exposure to high temperature.
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
Photosynthesis of a tree canopy is driven or influenced by
photosynthetically active solar radiation (PAR).
air temperature (T).
the total leaf area (LAI).
soil moisture (REW).
air humidity (VPD).
The annual cycle of photosynthesis mainly follows
the changes in soil temperature.
the changes in light.
the changes in CO2 concentration.
the changes in air temperature.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
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.