The Effect of Carbon Dioxide Levels on Photosynthesis
When the concentration of carbon dioxide is low the rate of photosynthesis is also low. This is because the plant has to spend a certain amount of time doing nothing, waiting for more carbon dioxide to arrive.
Increasing the concentration of carbon dioxide increases the rate of photosynthesis. The time spent idle becomes less and less.
There is a point at which further addition of carbon dioxide will not increase the rate of photosynthesis. The enzymes controlling the reaction are working as fast as possible, so the excess carbon dioxide cannot be utilized. Carbon dioxide is not the limiting factor at this point.
