Photosynthesis rate was measured in a leaf at increasing light intensities, with constant CO2 and temperature.
Why does the curve plateau at high light intensity?
- Acheck_circle
Light is no longer limiting; another factor (CO2, temperature, or enzymes) limits the rate
- B
Photosystems run out of electrons permanently
- C
Chlorophyll cannot absorb red light at high intensity
- D
Light directly destroys photosystems above any threshold
Explanation
Light absorption saturates the photosystems. Beyond that, CO2 availability, Calvin cycle enzyme kinetics, or temperature limit overall rate.