Question:
Transpiration decreases as air becomes drier.
Response:
To transform atmospheric CO2 into organic molecules, plants can use the energy from
atmospheric oxygen.
sun light.
soil heat.
soil nutrients.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
Carbon capture is performed by the green parts of plants via photosynthesis.
Photosynthesis of a tree canopy is driven or influenced by
atmospheric CO2.
photosynthetically active solar radiation (PAR).
soil moisture (REW).
air humidity (VPD).
the total leaf area (LAI).
air temperature (T).
Photoinhibition means the decrease in photosynthesis due to
exposure to shortage of soil moisture.
exposure to excess of light.
exposure to high temperature.
exposure to excess of CO2.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
What is the source of carbon that is assimilated in photosynthesis?
Soil nutrients
Atmospheric CO2
Soil water
Solar radiation
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
The rate of respiration decreases with temperature.
Carbon becomes locked as part of the accumulating plant biomass as plants grow.
As plants respire, they release
carbon dioxide.
oxygen.
Photosynthesis releases oxygen whereas respiration releases CO2.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
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.
