Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, IL 60637.
Proc Natl Acad Sci U S A. 1987 Jun;84(12):4103-7. doi: 10.1073/pnas.84.12.4103.
In the traditional Z scheme of photosynthesis the Emerson effects of red drop (decline in yield of photosynthesis in far-red light) and enhancement (of far-red yield by supplementary short-wavelength light) are taken to be evidence for the coupling in series of two photosystems that absorb unsymmetrically in the far-red region of the spectrum. An alternative explanation for red drop and enhancement is proposed here that does not invoke the series-coupling hypothesis. It is suggested that the Emerson effects may be due to the drop in intensity of radiation from sample absorption, which causes a photochemical loss when the reaction shuts off at depth in the medium. The effects of oxygen, carbon dioxide, and temperature on the yield may also be interpreted in terms of this model.
在传统的光合作用 Z 方案中,红降(远红光下光合作用产量下降)和增强(补充短波长光对远红光产量的增强)的爱默生效应被认为是两个光系统串联耦合的证据,这两个光系统在光谱的远红区域不对称地吸收光。本文提出了一种替代的解释,不涉及串联耦合假设,认为红降和增强可能是由于样品吸收导致辐射强度下降,当反应在介质深处关闭时会引起光化学损失。该模型还可以解释氧气、二氧化碳和温度对产量的影响。