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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 Î¼s with the Handy PEA

Fk (F300 μs)

Fluorescence intensity at 300 Î¼s

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