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以无柄小叶榕幼苗为研究材料,研究了不同NaCl浓度处理对无柄小叶榕气体交换、叶绿素荧光和抗氧化酶活性的影响。结果表明:在低浓度NaCl胁迫(50mmol/L)处理7d后,无柄小叶榕净光合速率(Pn)、气孔导度(Gs)和胞间CO2浓度(Ci)分别下降24%、31%和30%。低浓度NaCl处理并没有引起光化学猝灭(qP)和开放PSII反应中心激发能捕获效率(F’v/F’m)的下降;低浓度NaCl胁迫下无柄小叶榕Pn的下降主要是气孔因素引起的;高浓度NaCl胁迫(200mmol/L)处理7d后,Pn、Gs、Ci、qP和F’v/F’m分别下降了81%、54%、51%、72.7%和87.6%。表明高浓度NaCl胁迫下无柄小叶榕Pn的下降是由气孔因素和非气孔因素共同作用的结果,即除了降低气孔因子外,还通过降低F’v/F’m和qP,从而降低电子传递速率和Pn;高浓度NaCl胁迫还使非光化学猝灭(NPQ)、MDA含量、SOD和POD活性显著上升。表明尽管高浓度NaCl胁迫诱导一定程度的光能耗散,但仍不能及时地耗散过剩的激发能,导致了膜脂过氧化的发生。
The seedlings of fig leafless Banyan were used as materials to study the effects of different concentrations of NaCl on the gas exchange, chlorophyll fluorescence and antioxidant enzyme activities of fig leafless. The results showed that the net photosynthetic rate (Pn), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of Ficus microcarpa decreased by 24% and 31%, respectively, after treated with low concentration NaCl stress 30%. Low concentrations of NaCl did not induce the decrease of photochemical quenching (qP) and capture efficiency (F’v / F’m) of open PSII reaction center. The decrease of Pn of Ficus microcarpa was mainly caused by stomatal factors (Pn, Gs, Ci, qP and F’v / F’m decreased by 81%, 54%, 51%, 72.7% and 87.6% respectively after treated with 200mmol / L NaCl for 7 days. The results showed that the decrease of Pn of Ficus microcarpa was induced by stomatal and non-stomatal factors under the condition of high concentration of NaCl stress. In addition to the reduction of stomatal factor, the decrease of F’v / F’m and qP decreased the electron transfer Rate and Pn. High concentration NaCl stress also significantly increased NPQ, MDA content, SOD and POD activity. The results showed that although high concentration of NaCl induced a certain degree of light energy dissipation, it still could not dissipate excess excitation energy in time, leading to membrane lipid peroxidation.