What is the source of carbon that is assimilated in photosynthesis?
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
Transpiration decreases as air becomes drier.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
In some part of the stems, some photosynthesis may also occur.
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 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.
Photoinhibition means the decrease in photosynthesis due to
exposure to shortage of soil moisture.
exposure to excess of CO2.
exposure to excess of light.
exposure to high temperature.
exposure to shortage of soil moisture
exposure to high temperature
exposure to excess of light
exposure to excess of CO2
Almost half of the total biomass of a tree may be allocated to the roots.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
Carbon becomes locked as part of the accumulating plant biomass as plants grow.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
The rate of respiration decreases with temperature.
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.