PF	instantaneous chlorophyll fluorescence
MR	modulated 820 nm light reflection
DF	chlorophyll a delayed fluorescence
PSI	photosystem I
PSII	photosystem II
P680	PSII reaction center
P700	PSI reaction center
N	number of QA reduction events
RC/CSO	density of PSII RC per unit area
TRO/ABS	ratio of captured light energy to absorbed light energy
ETO/TRO	efficiency of electron transport at QA-
ABS/RC	light energy absorbed by the unit reaction center
PIABS	performance index (potential) for energy conservation from photons absorbed by PSII to the reduction of intersystem electron acceptors
REO/ETO	efficiency of an electron beyond QA− reduces PSI acceptors
Pn	net photosynthetic rate
QA	photosystem II primary quinone acceptor
QB	photosystem II secondary quinone acceptor
PQ	plastoquinone
VPSI	maximum falling slope of the MR/MRO curve
VPSII -PSI	maximum rising slope of the MR/MRO curve
OEC	Oxygen-evolving complex
L1, L2 and L3	amplitudes of the DF decay kinetic components