Table 2.
Measured and calculated parameters derived from fast fluorescence kinetics
| Parameter | Name and basic physiological interpretation |
|---|---|
| Basic JIP-test parameters derived from the OJIP transient2,3,4,6 | |
| F t | Fluorescence level at time t |
| F m = F P | Maximum fluorescence (the measured “peak” F P value) |
| V t = (F t − F 50 μs)/(F m − F 50 μs) | Relative variable fluorescence at time t, (V J, V I at 2, 30 ms) |
| Area | Area above the OJIP curve between F 0 and Fm and the Fm asymptote |
| S m = Area/(F m − F 50 μs) | Normalized area; proportional to the size of plastoquinone pool |
| Quantum yields and probabilities2,3,5,6,7 | |
| φ Po = F V /F m = 1 − (F 50 μs/F m) | Maximum quantum yield of primary PSII photochemistry |
| ψ ET2o = 1 − V J | Probability with which a PSII trapped electron is transferred from reduced QA to QB |
| Ψ RE1o = 1 − V I | Probability with which a PSII trapped electron is transferred from reduced QA beyond PSI |
| Specific energy fluxes expressed per active PSII reaction center (RC)2,3,5,7 | |
| ABS/RC = (dV/dt o/V J) × (1/φ Po) | Apparent antenna size of active PSII RC |
| TR/RC = dV/dt o/V J | Maximal trapping rate of absorbed photons in RC |
| ET/RC = (dV/dt o/V J) × (1 − V J) | Electron transport flux from reduced QA to QB in active RC |
| DI/RC = [dV/dt o/V J] × [1/(F 0/F m)] | Effective dissipation of energy in active RC |
| Connectivity among PSII units4,7,8 | |
| W E = 1 − [(F 2ms − F 300 μs)/(F 2ms − F 50 μs)]1/5 | Model-derived value of relative variable fluorescence at 100 μs calculated for unconnected PSII units |
| W = (F 100 μs − F 50 μs)/(F 2ms − F 50μs) | Relative variable fluorescence at 100 μs |
| C = (W E − W)/[V J × W × (1 − W E)] | Curvature constant of initial phase of the O–J curve |
| p 2G = C × [F 50μs/(F 2ms − F 50μs] | Overall grouping probability |
| p = [p 2G × (F m/F 50μs − 1)]/[1 + p 2G × (F m/F 50μs − 1)] | Connectivity parameter |
| ω = p × [(F m − F 50μs)/F m] | Probability of the connectivity among PSII units |