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. 2021 Mar 10;10(3):521. doi: 10.3390/plants10030521

Table 1.

Definitions of the chlorophyll fluorescence parameters and their calculation.

Parameter Definition Calculation
ΦPSII The effective quantum yield of PSII photochemistry (Fm′ − Fs)/Fm′
ΦNPQ The quantum yield of regulated non-photochemical energy loss in PSII, that is heat dissipation for photoprotection Fs/Fm′ − Fs/Fm
ΦNO The quantum yield of non-regulated energy loss in PSII Fs/Fm
NPQ The non-photochemical quenching that reflects heat dissipation of excitation energy (Fm − Fm′)/Fm′
q p The photochemical quenching, that is the redox state of the plastoquinone pool, is a measure of the number of open PSII reaction centers (Fm′ − Fs)/(Fm′ − Fo′)