How does temperature affect photosynthesis?

Temperature affects photosynthesis by influencing enzyme activity that controls both light-independent reactions and, indirectly, the overall efficiency of the process. Since photosynthesis is enzyme-driven, its rate depends on how temperature impacts these enzymes.

At low temperatures, enzyme activity slows down, reducing the rate of biochemical reactions in the Calvin cycle. This leads to slower carbon fixation and lower glucose production.

As temperature increases, enzyme activity improves, and the rate of photosynthesis rises until it reaches an optimum temperature range. Within this range, enzymes function at maximum efficiency, and photosynthesis proceeds at its highest rate.

Beyond the optimum level, high temperatures begin to denature enzymes, altering their structure and reducing their functionality. This results in a decline in photosynthesis. Additionally, higher temperatures can increase the rate of photorespiration, which reduces overall efficiency.

Temperature also affects stomatal behavior. In extreme heat, stomata may close to prevent water loss, limiting carbon dioxide intake and further reducing photosynthetic rate.

Overall, temperature is a critical factor that regulates photosynthesis, with both low and excessively high temperatures negatively impacting the process.