Revisiting JIP-test: An educative review on concepts, assumptions, approximations, definitions and terminology

The aim of this educative review is, by revisiting the JIP-test as introduced and further elaborated and extended by Professor Reto J. Strasser and his research group, to clarify concepts, assumptions, and approximations on which it is based, as well as definitions and terms it uses, reminding that it is meant to evaluate impacts of environmental - stresses factors and/or perturbations - on the photosynthetic structure and function. It analyses how the JIP-test, based on the Theory of Energy Fluxes and adopting Duysens' concept, translates the OJIP polyphasic chlorophyll a fluorescence rise kinetics, emitted by PSII, into biophysical parameters to be compared. The interpretation of the OJIP sequential steps and in-between phases, the definitions/meanings and formulae derivations of quantum yields, probabilities, efficiencies, specific energy fluxes, inactive PSII reaction centres, and performance indexes (PIABS, PItotal) is addressed in detail. OJIP normalizations and subtractions providing semiquantitative information are also discussed.