PHOTOSYNTHESIS IN RELATION TO LIGHT-INTENSITY AND WAVELENGTH, AND THE PROBLEM OF CHROMATIC AND NONCHROMATIC ADAPTATION

Chromatic and nonchromatic adaptation of photosynthesis is analyzed on the basis of the previously proposed approach to quantitative analysis of photosynthetic adaptation to environmental factors and the model of photosynthesis as a chain of coupled cyclic reactions. It is demonstrated that only two types of chromatic adaptation can exist in theory. The first type is adaptation based on regulation from the level of photosynthesis or from size of the flux of usable light energy. In this case, the effect of wavelength change can be compensated for by change of light intensity. The second type is adaptation realized with the involvement of a special photoregulatory system spectrally distinct from the action spectrum of photosynthesis. This type of chromatic adaptation is not reducible to purely light-related adaptation. Criteria are proposed that make it possible to delimit these two types of chromatic adaptation.