Emerson Enhancement Effect in Chloroplast Reactions.

The discovery of the Emerson enhancement effect in photosynthesis (3-6, 8) led to the suggestion that there are 2 photochemical reactions necessary for complete photosynthesis. A likely hypothesis is that the 2 reactions are carried on by different forms of chlorophyll a (10, 11). The enhancement effect in photosynthesis has been studied extensively in several laboratories (19) and it has been shown (12, 14, 15) that the effect also occurs ill 02 evolution in the Hill reaction using quinone as the electron acceptor. (iovindjee et al. (13) have recently reported the existence of the Emerson enhancement effect in NADP photoreduction by spinach chloroplasts using white (fluorescent) supplementary light. This paper deals w\vith observations on the enhancement of NADP lphotore(luction and 0., evolution in chloroplast preparationss, using both white and monochromatic lights.