模拟酸雨对烤烟叶片光合特性和叶绿素荧光参数的影响

以烤烟为供试材料,采用土培盆栽的方法研究了不同pH值的模拟酸雨(pH5.6、pH4.5、pH4.0、pH3.5、pH3.0、pH2.5、pH2.0)对烤烟叶片叶绿素含量、气体交换和叶绿素荧光参数的影响.结果表明:pH≥3.5处理的轻度酸雨对烤烟Chl.a含量影响不大,但pH≤3.5处理烤烟叶片Chl.b和总叶绿素含量显著下降.pH≤2.5模拟酸雨使烤烟叶片净光合速率(Pn)、气孔导度(Ls)、胞间CO2浓度(Ci)、叶面饱和蒸气压力亏缺(VPD)显著降低,使烤烟叶片的气孔限制值(Ls)和潜在水分利用效率(WUEi)显著升高,模拟酸雨使pH2.0处理烤烟叶片的蒸腾速率(Tr)和pH2.5处理的瞬时水分利用效率(WUE)显著降低.pH≥3.5处理的光合有效量子产量(EQY)、光合电子传递速率(ETR)和光化学猝灭(qP)与对照差异不大,但pH≤3.0处理明显降低;烤烟叶片的非光化学猝灭呈先升高后降低趋势,pH≥3.5处理的非光化学猝灭(NPQ)明显高于pH≤3.0处理.

Effects of simulated acid rain on photosythesis and chlorophyll fluorescence parameters of flue-cured tobacco leaves

Chlorophyll(chl)contenta,gas exchange and chlorophyll fluorescence parameters were measured to determine the effects of simulated acid rain with different Ph values(Ph 5.6.Ph 4.5,Ph 4.0,Ph 3.5,Ph 3.0,Ph 2.5,Ph 2.0)on the photosynthetic characteristics of flue-cured tobacco leaves.The results showed that simulated acid rain with pH≥3.5 had no significant influence on chl.a contents but chl.b and total chlorophyl contents were significantly reduced with simulated acid rain with pH≤3.5.Carotenoid contents,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO_2 concenffation(C_I)and vaporpressure default(VPD)at the leaf surface in treatments with acid rain of pH≤2.5 were significantly lower than that of the control.The stoma limited value(Ls)and intrinsic water utilization efficiency(WUEi)in the treatments with acid rain of pH≤2.5 were significantly hi er than that of the control and the treatment of Ph 4.5.Simulated acid rain significantly reduced the transpiration rate at pH 2.0 and water utilization efficiency(WUE)at Ph 2.5.There were no significant differences in effective quantum yield(EQY),photochemical electron transport rate(ETR),and photochemical quenching(Qp)between the treatments of pH≥3.5 and the control,while they were reduced in the treatments of pH≤3.0.Non-photochemical quenching(NPQ) in the treatment of pH≥3.5 was higher than that in the treatments of pH≤3.0.