Variation of enhancement of photosynthesis with conditions of algal growth

The Emerson effect was observed as an enhancement of photosynthesis in long-wavelength red light when beams of shorter wavelength were added. Two light beams of wavelengths 650 and 694 mmicro, respectively, when presented together, gave a photosynthetic rate higher than the sum of the rates obtained separately. The amount of enhancement of photosynthesis depends upon the growth conditions of algal cells, and specifically on their phosphate metabolism.