EFFECTS OF SO2-3 AND HCO-3 ON CHLOROPHYLL FLUORESCENCE IN DUNALIELLA SALINA 1009

Abstract:

An unicellular green alga DUnaliella salina 1009 was used as a plant cell model to study the effects of SO^2-₃ and HCO^-₃ on chlorophyll fluorescence under high light intensity (1000 μmol m^-2s^-1) with measurements by modulation pulse fluorometer (PAM). The initial fluorescence (Fo) was induced by a weak measuring light, and the actinic light was at 150 μmol m^-2s^-11, while maximum fluorescence (Fm) was produced under a strong saturated pulse light (6000 μmol m^-2s^-1). The results indicated that the photosynthesis of D. salina 1009 was stimulated by low concentration of SO^2-₃ (1 mmol/L) under high light intensity (1000 μmol m^-2s^-1) for 1 h. With the increasing concentrations of SO^2-₃ (5, 25, 50, 100 mmol/L),the Fv/Fm, q_N，q_P and PS II in D. salina 1009 decreased, and the photoinhibition was obvious. Photoinhibition induced by SO^2-₃ in the presence of HCO^-₃ under high light intensity was reduced, and could be rapidly recovered under low light intensity(40 μmolm^-2s^-1). The results showed a protective role of HCO^-₃ against the SO^2-₃ damage under high light intensity (1000 μmol m^-2s^-1).