A reexamination of the Kitajima and Butler (1975) model for relating chlorophyll a fluorescence to photochemistry

The main assumptions of the well-known Kitajima and Butler (1975) model, describing the relationship between the ratio of the maximum variable chlorophyll a fluorescence to the maximum fluorescence (FV/FM) and the photochemical quantum yield of PSII (ΦPo), have been analyzed. Using the experimental data from the literature, potential "weak points" of this model are discussed, as well as the reasons for the differences between the FV/FM values and the actual ΦPo values. Special attention is focused on the fluorescence measurement procedures using the saturating single turnover light flashes and the saturating multiple turnover light pulses. It is concluded that if the FV/FM measurements are made properly, the value of ΦPo can indeed be estimated.