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Table 1 Summary of parameters, formulae and their description using data extracted from chlorophyll a fluorescence (OJIP) transient.

From: CO2assimilation, ribulose-1,5-bisphosphate carboxylase/oxygenase, carbohydrates and photosynthetic electron transport probed by the JIP-test, of tea leaves in response to phosphorus supply

Fluorescence parameters

Description

Fluorescence parameters

Description

Ft

Fluorescence intensity at time t after onset of actinic illumination

F50 μsor F20 μs

Minimum reliable recorded fluorescence at 50 μs with the PEA- or 20 μs with Handy-PEA-fluorimeter

F100 μs and F300 μs

Fluorescence intensity at 100 and 300 μs, respectively

FJ and FI

Fluorescence intensity at the J-step (2 ms) and the I-step (30 ms), respectively

FP (= Fm)

Maximum recorded (= maximum possible) fluorescence at P-step

Area

Total complementary area between fluorescence induction curve and F = Fm

Derived parameters

 

Selected OJIP parameters

 

F0 ≅ F50 μsor F0 ≅ F20 μs

Minimum fluorescence, when all PSII RCs are open

Fm = FP

Maximum fluorescence, when all PSII RCs are closed

VJ = (F2 ms - Fo)/(Fm - Fo)

Relative variable fluorescence at the J-step (2 ms)

VI = (F30 ms - Fo)/(Fm - Fo)

Relative variable fluorescence at the I-step (30 ms)

Mo = 4 (F300 μs - Fo)/(Fm - Fo)

Approximated initial slope (in ms-1) of the fluorescence transient V = f(t)

Sm = ECo/RC = Area/(Fm - Fo)

Normalized total complementary area above the OJIP (reflecting multiple-turnover QA reduction events) or total electron carriers per RC

Yields or flux ratios

 

φPo = TRo/ABS = 1-(Fo/Fm) = Fv/Fm

Maximum quantum yield of primary photochemistry at t = 0

φEo = ETo/ABS = (Fv/Fm) × (1 - VJ)

Quantum yield for electron transport at t = 0

ψEo = ETo/TRo = 1-VJ

Probability (at time 0) that a trapped exciton moves an electron into the electron transport chain beyond QA-

φDo = DIo/ABS = 1-φPo = Fo/Fm

Quantum yield at t = 0 for energy dissipation

δRo = REo/ETo = (1 - VI)/( - VJ)

Efficiency with which an electron can move from the reduced intersystem electron acceptors to the PSI end electron acceptors

φRo = REo/ABS = φPo × ψEo× δRo φ

Quantum yield for the reduction of end acceptors of PSI per photon absorbed

Specific fluxes or activities expressed per reaction center (RC)

 

ETo/RC = (Mo/VJ) × ψEo = (Mo/VJ) × (1-VJ)

Electron transport flux per RC at t = 0

DIo/RC = (ABS/RC) - (TRo/RC)

Dissipated energy flux per RC at t = 0

REo/RC = (REo/ETo) × (ETo/RC)

Reduction of end acceptors at PSI electron acceptor side per RC at t = 0

ETo/CSo = (ABS/CSo) × φEo

Electron transport flux per CS at t = 0

TRo/CSo = (ABS/CSo) × φPo

Trapped energy flux per CS at t = 0

DIo/CSo = (ABS/CSo) - (TRo/CSo)

Dissipated energy flux per CS at t = 0

REo/CSo = (REo/ETo) × (ETo/CSo)

Reduction of end acceptors at PSI electron acceptor side per CS at t = 0

Density of RCs

 

RC/CSo =φPo × (ABS/CSo) × (VJ/Mo)

Amount of active PSII RCs per CS at t = 0

Performance index

 

PIabs = (RC/ABS) × (φPo/(1 - φPo)) × (ψo/(1 - ψo))

Performance index (PI) on absorption basis

PItot, abs = (RC/ABS) × (φPo/(1-φPo)) × (ψEo/(1 - ψEo)) × (δRo/(1 - δRo))

Total PI, measuring the performance up to the PSI end electron acceptors