Question

The compensation point of $C{O_2}$ for ${C_3}$ plant is

Answer 1

Hint: We must have to know that the photosynthesis and the respiration are balanced in compensation point. During respiration, there is an uptake of oxygen that takes place and it should be equal to the oxygen which is released in the time of photosynthesis. And the compensation point is attained as the photosynthetic activity decreases and the respiration will be increased. Hence, the amount of liberation of oxygen is equal to the amount of liberation carbon dioxide released in the time of respiration.

Complete answer:
We need to remember that in the case of plants, the light intensity at which the photosynthesis and the respiration will cancel each other and that point is considered a compensation point. If it is below this point, the plant will not grow due to the use of carbohydrates.
The plants will not absorb the carbon dioxide from the atmosphere. Hence, the levels of carbon dioxide should be the same as the rate of carbon dioxide released in the time of respiration and photorespiration and thus the compensation point of carbon dioxide. And the compensation point of $C{O_2}$ for ${C_3}$ plant is equal to $250 - 100ppm$.

Note:
 We need to know that in the compensation point the light intensity as a result of which the net rate of oxygen produced is almost equal to zero. And at this point the utilization of oxygen by the plant because of the cellular respiration which is equal to the rate of oxygen produced by the photosynthesis. The light will influence the utilization of carbon dioxide in plants. Because, it provides the energy for the pigments of photosynthesis and it will convert to carbon dioxide.