The Emerson Enhancement Effect provided evidence for the existence of:

✅Explanation:
The Emerson Enhancement Effect was discovered by Robert Emerson in the 1950s and provided key evidence for the existence of two distinct photosystems in the process of photosynthesis. Emerson found that when plants were exposed to light of two different wavelengths (one primarily absorbed by Photosystem II and the other by Photosystem I), the rate of photosynthesis was greater than when light of a single wavelength was used. This enhancement effect showed that the two photosystems (Photosystem I and Photosystem II) work together to drive photosynthesis more efficiently.

🛑 Additional Information:
-Photosynthesis occurs in the chloroplasts of plant cells and on the plasma membrane of some bacterial cells. It is of the two-stage process-
-The first stage is a light reaction where light energy is converted into ATP and NADPH.
-The second stage is the dark reaction where ATP and NADPH, generated in the light reaction, are used for the reduction of carbon dioxide and water to carbohydrates.
-Emerson found that red light (above 680nm) which is photosynthetically ineffective, can be made effective by supplementing it with beam shorter wavelength (red beam below 680nm).
-After that, the quantum yield in the combined beam is more than the sum of the total yield in two separate beams.
-Shorter than 680nm + longer than 680nm = Emerson effect.
So, the enhancement (increase) in quantum yield by two different wavelengths of light is called Emerson and enhancement effect.
Additional Information
-Emerson and Arnold worked on chlorella and gave only monochromatic light, longer than 680nm wavelength, then the quantum yield is suddenly dropped down this event is called a red drop.