亚硫酸氢钠影响脐橙叶片光合作用的原因

Causation of Sodium Bisulfite Affect Photosynthesis in Leaves of Umbilical Orange

经浓度低于8mmol·L-1的NaHSO3溶液处理的脐橙叶片净光合速率(Pn)、电子传递速率ETR和叶绿体光合放O2活性升高,光合色素含量、初始荧光Fo和PS 的光化学效率Fv/Fm变化不明显;而12mmol·L-1的NaHSO3溶液处理后,Pn、光合色素含量、Fv/Fm、ETR和光合放O2活性显著下降,Fo则明显升高。与对照相比,处理组叶绿体内·O2-、H2O2的含量显著降低。结果显示,低浓度NaHSO3溶液能通过清除·O2-、H2O2等有害物质而促进光合作用。高浓度NaHSO3溶液因过量的HSO3-以及由它产生的SO2均具有漂白作用,最终导致脐橙发生光合作用的光抑制。

The net photosynthetic rate(Pn), electron transfer rate(ETR) in leavesof umbilical orange and photosynthetic O_2 evolution activities of the chloroplastsgo up after treatment by under 8 mmol·L^(-1) sodium bisulfite solution,and photosyntheticpigment content, initial fluorescence(Fo) and photochemical efficiency of PSⅡ (Fv/Fm)change unsignally. The Pn , photosynthetic pigment content , Fv/Fm,ETR and photosynthetic O_2 evolution activities of the chloroplasts marked decrease and Fo increase after deal with sodium bisulfite of 12 mmol·L^(-1) concentrations . After treated by sodium bisulfite solution, the content of·O_2^- and H_2O_2 in the chloroplastswas much lower than control(H2O).The results indicated that sodium bisulfite at low concentrations could increase photosynthetic rate by to rid ·O_2^-?H_2O_2 etc. baneful substance.And that sodium bisulfite at high concentrations,because superfluous HSO_3^- along with by it procreant SO_2 all have blanch action,finally conducing the umbilical orange take place photoinhibition of photosynthesis.