Question:
Plant respiration captures CO2.
Response:
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
Carbon becomes locked as part of the accumulating plant biomass as plants grow.
The annual cycle of photosynthesis mainly follows
the changes in CO2 concentration.
the changes in light.
the changes in soil temperature.
the changes in air 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.
As plants respire, they release
oxygen.
carbon dioxide.
Almost half of the total biomass of a tree may be allocated to the roots.
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.
Transpiration decreases as air becomes drier.
Photosynthesis of a tree canopy is driven or influenced by
air temperature (T).
atmospheric CO2.
photosynthetically active solar radiation (PAR).
the total leaf area (LAI).
soil moisture (REW).
air humidity (VPD).
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
In some part of the stems, some photosynthesis may also occur.
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.
