CBSE Class 10 Answered

The amount of light intensity on the light curve where the rate of respiration is equal to the rate of photosynthesis is called compensation point. At this point, the uptake of CO₂ through photosynthetic pathway is exactly equivalent to the respiratory release of CO₂, and the uptake of O₂ by respiration is exactly equivalent to the photosynthetic release of O₂. With further increase in light intensity, the plant begins to photosynthesize more than it respires and the sugars produced get stored as starch. At the compensation point, the net carbon dioxide assimilation is zero. Leaves release CO₂ by photorespiration and day respiration, but CO₂ is also converted into carbohydrate by photosynthesis. The compensation point for light intensity varies according to the type of plant, but it is typically 40 to 60 W/m² for sunlight.