At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
In some part of the stems, some photosynthesis may also occur.
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.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
The annual cycle of photosynthesis mainly follows
the changes in soil temperature.
the changes in light.
the changes in air temperature.
the changes in CO2 concentration.
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 general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
Photoinhibition means the decrease in photosynthesis due to
exposure to excess of light.
exposure to high temperature.
exposure to excess of CO2.
exposure to shortage of soil moisture.
Transpiration decreases as air becomes drier.
As plants respire, they release
Photosynthesis releases oxygen whereas respiration releases CO2.
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.
Carbon becomes locked as part of the accumulating plant biomass as plants grow.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.