Ontogenetic approach to the assessment of plant resistance to prolonged stress using chlorophyll fluorescence induction method

The review deals with objective reasons that limit the use of chlorophyll fluorescence induction kinetics (Chl FIK) method in plant ecology. Based on the ontogenetic approach (analysis and comparison of the dynamics of the Chl fluorescence ratio F-p/F-s and physiological characteristics of plant leaves in ontogeny) possible criteria for the estimation of general plant resistance of photosynthetic apparatus (PSA) to prolonged stress affects are proposed. One of these criteria is the presence or absence of a steady-state phase in the dynamics of Chl fluorescence ratio F-p/F-s (or R-fd) of plant leaves after they stop growing. We also propose to use the duration of the steady-state phase and variability of Chl fluorescence ratios R-fd and F-p/F-s in this period for quantitative assessment of plant PSA resistance to prolonged stress during plant leaf ontogeny.