Question

Given abundant sunlight, what would be a factor that limits the rate of photosynthesis? Explain your answer.

Answer 1

Ans. Carbon dioxide ( CO​​​​​2) is one of the limiting factor in photosynthesis. Glucose is synthesized during photosynthesis from CO​​​​​2 and H​​​​​​2​​​​​O during photosynthesi by using energy from sunlight. When atmospheric​ CO2 concentration is less, photosynthesis does not occur efficiently due to lack of CO​​​​​2 as raw material. As the level of CO​​​2 concentration increases the rate of photosynthesis increases. This limiting factor reduces glucose production during photosynthesis when present at low concentration in the atmosphere. Atmospheric carbon dioxide concentration of 300 ppm is optimum for photosynthesis. Below this concentration there is reduction in rate of photosynthesis hence less glucose is synthesized. At very low atmospheric carbon dioxide concentration photosynthesis is inhibited. But C​​​​​​4​​​​​ plants such as sugarcane, maize can use lesser CO​​​​​2 concentration in the atmosphere as compared to C​​​​​​3​​​ plants. This is due to the presence of kranz anatomy in leaves of C4 plants.