The Effect of Low Concentration of SO_2 on the Content of Chlorophyll and Carotenoid and Chlorophyll Fluorescence in Chrysanthemum sp.Leaves

After being treated with 0.3 mg·L~(-1) of SO_2 for one week,the contents of chlorophyll and carotenoid and the kinetics of chlorophyll fluorescence increased obviously.Apparent photosynthetic electron transport ratio(ETR) and the quanta efficiency of the non-cyclic electron transport(Yield) increased while the content of chlorophyll and carotenoid decreased when treated for over a week.After being treated for six weeks,the kinetics of chlorophyll fluorescence and the non-photochemical quenching coefficient(q_N) increased obviously while the contents of chlorophyll and carotenoid,the potential activity of photosystem II(F_V/F_0) ETR and the yield of leaves of C.sp.decreased obviously,but the maximal photochemical efficiency of PSII in the dark(F_V/F_m) and q_P being little influenced.