Question:
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
Response:
As plants respire, they release
oxygen.
carbon dioxide.
Carbon capture is performed by the green parts of plants via photosynthesis.
Photosynthesis of a tree canopy is driven or influenced by
soil moisture (REW).
the total leaf area (LAI).
atmospheric CO2.
photosynthetically active solar radiation (PAR).
air temperature (T).
air humidity (VPD).
The rate of respiration decreases with temperature.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
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.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
soil nutrients.
sun light.
atmospheric oxygen.
soil heat.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
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.
What is the source of carbon that is assimilated in photosynthesis?
Atmospheric CO2
Solar radiation
Soil nutrients
Soil water
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
