The compensation point of CO2 for C3 plants is
25-100 ppm
The compensation point for CO2 is the point where the plant does not absorb any CO2 from the surrounding as the levels of CO2 used in photosynthesis is equal to the amount of CO2 released by respiration and photorespiration. In C3 plants, this value of the compensation point for CO2 is 25-100 ppm.