Question:
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
Response:
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.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
soil nutrients.
atmospheric oxygen.
sun light.
soil heat.
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of 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.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
As plants respire, they release
oxygen.
carbon dioxide.
The rate of respiration decreases with temperature.
What is the source of carbon that is assimilated in photosynthesis?
Atmospheric CO2
Soil nutrients
Solar radiation
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.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
Photoinhibition means the decrease in photosynthesis due to
exposure to excess of light.
exposure to high temperature.
exposure to shortage of soil moisture.
exposure to excess of CO2.
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.
