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Table 5 Summary of parameters, formulae and their descriptions using data extracted from the OJIP test

From: Comparison of investigation methods of heat injury in grapevine (Vitis) and assessment to heat tolerance in different cultivars and species

Fluorescence parameters Fluorescence parameters description
Extracted parameters  
Ft Fluorescence intensity at time t after onset of actinic illumination
F50 μs Minimum reliable recorded fluorescence at 50 μs with the Handy PEA
Fk (F300 μs) Fluorescence intensity at 300 μs
FP Maximum recorded (=maximum possible) fluorescence at P-step
Area Total complementary area between fluorescence induction curve and F = Fm
Derived parameters  
Fo F50 μs Minimum fluorescence, when all PSII RCs are open
Fm = FP Maximum fluorescence, when all PSII RCs are closed
Vj = (Fj - Fo)/(Fm - Fo) Relative variable fluorescence at the J-step (2 ms)
Vi = (Fi - Fo)/(Fm - Fo) Relative variable fluorescence at the I-step (30 ms)
WK = (Fk - Fo)/(Fj - Fo) Representing the damage to oxygen evolving complex (OEC)
Mo = 4 (Fk - Fo)/(Fm - Fo) Approximated initial increment (in ms-1) of the relative variable fluorescence
Fv/Fm = 1- (Fo/Fm) Maximum quantum yield of primary photochemistry at t = 0
φEo = ETo/ABS = (Fm-Fj)/Fm Quantum yield for electron transport at t = 0
RCQA = φPo × (ABS/CSm) × (Vj/Mo) Amount of active PSII RCs (QA-reducing PSII reaction centers) per CS at t = m