Red light is more effective in photosynthesis because both the photosystems (PS I and PS II) absorb light of wavelengths in the red region (680 and 700 nm, respectively). Furthermore, blue light is absorbed by carotenoids, which pass the energy to the chlorophyll.
- Light in the red region is absorbed by chlorophyll.
- Since maximum absorption by chlorophyll occurs in red light, it is the most effective wavelength for photosynthesis.
- Green light is least effective in photosynthesis.