Emerson effect he noticed that at wavelengths of greater than 680 nm the efficiency of photosynthesis decreased abruptly despite the fact that this is a region of the spectrum where chlorophyll still absorbs light (chlorophyll is the green pigment in plants - it absorbs mainly the red and blue wavelengths from light, leaving the green light to bounce back and hit our eyes). When the plants were exposed to short-wavelength light, (less than 660 nm), the efficiency also decreased. Emerson then exposed the plants to both short and long wavelengths at the same time, causing the efficiency to increase greatly. He concluded
Chlorophyll hundred molecules per photosystem) is to absorb light. Having done so, these same centers execute their second function: the transfer of that light energy by resonance energy transfer to a specific chlorophyll pair in the reaction center of the photosystems. This pair effects the final function of chlorophylls, charge separation, leading to biosynthesis. The two currently accepted photosystem units are photosystem II and photosystem I, which have their own distinct reaction centres, named P680 and P700, respectively. These centres are named after the wavelength (in nanometers) of their red-peak absorption maximum. The identity, function and spectral properties of the types