Why is carbon dioxide concentration a limiting factor in photosynthesis?

Carbon dioxide concentration is a limiting factor in photosynthesis because it is a necessary reactant in the photosynthesis process.

Photosynthesis is the process by which green plants, algae and some bacteria convert light energy, usually from the sun, into chemical energy in the form of glucose. This process is vital for life on Earth as it is the primary source of all the organic compounds and most of the energy necessary for life. The general equation for photosynthesis is 6CO2 + 6H2O → C6H12O6 + 6O2, which shows that carbon dioxide is a key reactant.

Carbon dioxide enters the plant through small openings in the leaves called stomata. Inside the leaf, it gets used in the Calvin cycle, the second stage of photosynthesis, to produce glucose. If the concentration of carbon dioxide in the atmosphere is low, the rate of photosynthesis will be limited because there is not enough carbon dioxide available for the plant to convert into glucose. This is similar to any chemical reaction where the rate of reaction is dependent on the concentration of the reactants.

Furthermore, the concentration of carbon dioxide is not the only factor that can limit the rate of photosynthesis. Light intensity and temperature can also be limiting factors. If the light intensity is too low, the rate of photosynthesis will decrease because there is not enough energy to power the reaction. Similarly, if the temperature is too low, the enzymes that catalyse the photosynthesis reaction will not work efficiently, slowing down the rate of photosynthesis.

In conclusion, carbon dioxide concentration is a limiting factor in photosynthesis because it is a necessary reactant in the photosynthesis process. If the concentration of carbon dioxide is low, the rate of photosynthesis will be limited.