Question:
High soil moisture leads to decreased photosynthesis.
Response:
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
Almost half of the total biomass of a tree may be allocated to the roots.
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.
What is the source of carbon that is assimilated in photosynthesis?
Soil nutrients
Solar radiation
Atmospheric CO2
Soil water
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
The rate of respiration decreases with temperature.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
As plants respire, they release
oxygen.
carbon dioxide.
Photosynthesis releases oxygen whereas respiration releases CO2.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
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.
In some part of the stems, some photosynthesis may also occur.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
sun light.
soil heat.
atmospheric oxygen.
soil nutrients.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
The annual cycle of photosynthesis mainly follows
the changes in air temperature.
the changes in CO2 concentration.
the changes in light.
the changes in soil temperature.
Transpiration decreases as air becomes drier.
