Question:
What is the source of carbon that is assimilated in photosynthesis?
Soil water
Soil nutrients
Solar radiation
Atmospheric CO2
Response:
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.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
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.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
As plants respire, they release
carbon dioxide.
oxygen.
Photosynthesis releases oxygen whereas respiration releases CO2.
Photoinhibition means the decrease in photosynthesis due to
exposure to shortage of soil moisture.
exposure to excess of CO2.
exposure to high temperature.
exposure to excess of light.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
soil heat.
sun light.
atmospheric oxygen.
soil nutrients.
Almost half of the total biomass of a tree may be allocated to the roots.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
In some part of the stems, some photosynthesis may also occur.
