Photosynthetic apparatus performance and anatomical modulations of Alcantarea imperialis (Bromeliaceae) exposed to selenium during in vitro growth

Abstract

Ft -fluorescence at time t after the beginning of actinic illumination; FV/F0 -ratio of the de-excitation rate constants for photochemical and nonphotochemical events; OEC -oxygen-evolving complex; PItotal -total performance index, which measures the performance up until the final electron acceptors of PSI; RC/CSm -total number of PSII active reaction centers; Sm/tFmax -average fraction of open RC in the period of 0 to tFmax (time of maximum fluorescence production); VI -relative variable fluorescence at 30 ms (step I); VJ -relative variable fluorescence at 2 ms (step J); VK -relative variable fluorescence at 0.3 ms (step K); WK -the damage to OEC; WL -indicates disturbance in the thylakoid membranes, reducing the energetic connectivity between the PSII units; δR0 -efficiency/probability with which an electron from the intersystem electron carriers moves to reduce end electron acceptors at the PSI acceptor side (RE); φD0quantum yield of energy dissipation (at t = 0); φE0 -quantum yield of electron transport (at t = 0); φP0 = FV/Fm -maximum quantum yield of primary photochemistry of PSII reaction center (at t = 0); φR0 -quantum yield of reduction of end electron acceptors at the PSI acceptor side (RE); ψR0 -efficiency/probability by which electrons move from PSII to the PSI acceptor side.