- Light intensity, concentration of CO₂, and temperature are the primary factors affecting the rate of photosynthesis.
- At low light intensity, light is the limiting factor; as light increases, the limiting factor shifts to either CO₂ concentration or temperature, depending on which is in shortest supply.
- Temperature affects enzyme activity in photosynthesis; rates increase with temperature up to an optimum, then decline sharply due to enzyme denaturation. Higher CO₂ concentration generally increases the rate of photosynthesis until another factor becomes limiting.
- Photosynthesis rates are lowest at dawn and dusk due to low light intensity and cooler temperatures, peak around midday when light and temperature are optimal, and may dip slightly in very hot afternoons if stomata close to conserve water, reducing CO₂ uptake.
- To increase crop productivity: optimize light exposure (e.g., using grow lights or spacing plants), enrich greenhouse air with CO₂, maintain optimal temperature ranges, and select plant varieties adapted to local conditions.
Parent Tip: Review the logic above to help your child master the concept of affecting photosynthesis.
