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

F _t

Fluorescence intensity at time t after onset of actinic illumination

F _{50 μs}

Minimum reliable recorded fluorescence at 50 μs with the PEA fluorimeter

F_k (F_{300 μs})

Fluorescence intensity at 300 μs

F _P

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

Area

Total complementary area between fluorescence induction curve and F = Fm

ABS

Absorption of energy

TR

Trap of energy

CS

Excited Cross section

Derived parameters (Selected OJIP parameters)

F_o≅F_{50 μs}

Minimum fluorescence, when all PSII RCs are open

F_m = F_P

Maximum fluorescence, when all PSII RCs are closed

V_j = (F_{2 ms} -- F_o)/(F_m -- F_o)

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

V_i = (F_{30 ms} -- F_o)/(F_m -- F_o)

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

W_K= (F_{300 μs}-- F_o/(F_j-- F_o)

Represent the damage to oxygen evolving complex OEC

M_o = 4 (F_{300 μs} -- F_o)/(F_m-- F_o)

Approximated initial slope of the fluorescence transient

Yields or flux ratios

ϕ_Po = TR_o/ABS = 1-- (F_o/F_m) = F_v/F_m

Maximum quantum yield of primary photochemistry at t = 0

ϕ_Eo = ET_o/ABS = (F_v/F_m) × (1 -- V_j)

Quantum yield for electron transport at t = 0

ψ_Eo = ET_o/TR_o = 1 -- V_j

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

δ_Ro = (1 -- V_i)/(1 -- V_j)

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

Density of reaction centers.

RC_QA = ϕ_Po × (ABS/CS_m) × (V_j/M_o)

Amount of active PSII RCs (QA-reducing PSII reaction centers) per CS at t = m