Table 1.
Measured and calculated chlorophyll fluorescence parameters
| Parameters | Name and basic physiological interpretation |
|---|---|
| Measured or computed inputs for calculation of the key fluorescence parameters | |
| F, F′ | Fluorescence emission from dark- or light-adapted leaf, respectively |
| F 0 | Minimum fluorescence from dark-adapted leaf (PSII centers open); F 0 was not corrected for PSI fluorescence, and for the possible presence of reduced QB that could produce some reduced QA in darkness. |
| F m, F m ′ | Maximum fluorescence from dark- or light-adapted leaf, respectively (PSII centers closed) |
| F V = F m − F 0 | Maximum variable fluorescence from dark-adapted leaf |
| F 0 ′ = F 0/[(F V/F m) + (F 0/F m ′)] | Minimum fluorescence from light-adapted leaf12 |
| F s ′ | Steady-state fluorescence at any light level |
| α = χ/(χ + 76) | Absorbance of incident PAR (photosynthetic active radiation) by leaf9 |
| χ | Total chlorophyll content (in μmol m−2) |
| Key chlorophyll fluorescence parameters derived from the saturation pulse analysis | |
| F V /F m = 1 − (F 0 /F m ) | Estimated maximum quantum efficiency (yield) of PSII photochemistry1,7,10 |
| Φ PSII = (F m − F′)/F m ′ | Estimated effective quantum yield (efficiency) of PSII photochemistry at given PAR5 |
| ETR = 0.5 × α × PAR × Φ PSII | Rate of linear electron transport in PSII at given photosynthetic active irradiance (PAR), assuming that there is equal partitioning of absorbed light between PSI and PSII (constant value 0.5)4,5 |
| NPQ = (F m − F m ′)/F m ′ | Non-photochemical quenching3,8 |
| qP = (F m ′ − F s ′)/(F m ′ − F 0 ′) | Coefficient of photochemical quenching based on the “puddle” model (i.e., unconnected PSII units)2,4,6 |
| qL = qP × (F 0/F s ′) | Coefficient of photochemical quenching based on the “lake” model (i.e., fully connected PSII units)12 |
| qCU = (F m ′ − F s ′)/((p/(1–p)) × (F s − F 0 ′) + F m ′ − F 0 ′) | Coefficient of photochemical quenching based on the “connected units model” model (intermediate model)11,13 parameter p is defined in Table 2. |
| Φ NO = 1/[NPQ + 1 + qL(F m/F 0 − 1) | Quantum yield of non-regulated energy dissipation in PSII13 |
| Φ NPQ = 1 − Φ PSII − Φ NO | Quantum yield of pH-dependent energy dissipation in PSII13 |
Based on 1 Kitajima and Butler (1975); 2 Schreiber (1986); 3 Schreiber et al. (1988); 4 Björkman and Demmig (1987); 5 Genty et al. (1989); 6 Bilger and Björkman (1990); 7 Krause and Weis (1991); 8 Walters and Horton (1991); 9 Evans (1993); 10 Schreiber et al. (1995); 11 Lavergne and Trissl (1995); 12 Oxborough and Baker (1997); 13 Kramer et al. (2004)