The partial phototransformation quantum yields Φr and Φfr of phytochrome photoconversion are reexamined using adequate photokinetic methods. The principles of these methods based on formally ...integrated rate equations and difference equations, respectively, are represented. It is shown that the partial quantum yields determined hitherto using the equations derived by Butler et al. (1964) exhibit systematic errors if the initial absorbance at the irradiation wavelength exceeds a value of 0.009.
Before applying the kinetic analysis the photoconversion was confirmed to be a reaction of a two component system composed of only Pr and Pfr.
