Relationship between action spectra for chlorophyll a fluorescence and photosynthetic O₂ evolution in algae

Relative excitation spectra of chlorophyll a fluorescence are shown to be very close to relative action spectra of photosystem II O₂ evolution in seven micro- and macro-algae of five phyla. The conditions under which this correspondence should hold, based on theoretical considerations, and the applications of this correspondence to interpretation of fluorescence excitation spectra of chlorophyll a from natural populations are discussed. The spectra presented are interpreted in relation to the light-harvesting pigments and their association with the two photosystems.