+Corresponding author e-mail: csuftzf@163.com phone: 8615873162712 fax: 0731-85623458 Abbreviations: ABS/RC – absorption flux (of antenna Chls) per RC (also a measure of PSII apparent antenna size); CE – carboxylation efficiency; Ci – intercellular CO2 concentration; DI0/RC – dissipated energy flux per RC at t = 0; F0 – minimal fluorescence yield of the dark-adapted state; FJ – fluorescence intensity at the J-step (2 ms); FK – fluorescence intensity at 300 μs; FM – maximum fluorescence yield of the dark-adapted state; FV/FM – maximum quantum use efficiency; gs – stomatal conductance; IP-phase – the efficiency of electron transport around the PSI; M0 – approximated initial slope of the fluorescence transient; MR0 – first reliable recorded fluorescence at 0.7 ms; MRmin – the minimum fluorescence intensity; OEC – oxygen-evolving complex; PIABS – performance index; PN – maximum net photosynthetic rate; RE0/RC – the flux of electrons transferred from QA– to final PSI acceptors per PSII at t = 0; Sm – normalized total complementary area above the OJIP transient (reflecting single-turnover QA reduction events); TR0/RC – trapped energy flux (leading to QA reduction) per RC at t = 0; VPSI – maximum decrease in slope in the range of 0.7–3 ms of MR/MR0; VPSI+PSII – maximum increase in slope in the range of 7–300 ms of MR/MR0; δR0 – efficiency with which an electron can move from the reduced intersystem electron acceptors to the PSI end electron acceptors; ΦE0 – quantum yield for electron transport; ψE0 – probability that a trapped exciton moves an electron into the electron transport chain beyond QA. Acknowledgements: This research was funded by the National Natural Science Foundation of China (32072672), the Key Research and Development Project of Hunan Province (2017NK2171), the Scientific Innovation Fund for Post-graduates of Central South University of Forestry and Technology (20181007), and the Scientific Innovation Fund for Post-graduates of Central South University of Forestry and Technology (CX20192062). Conflict of interest: The authors declare that they have no conflict of interest.
