采用盆栽试验,以玉米品种CT505为材料,研究外源茉莉酸甲酯(MeJA)对盐(NaCl)胁迫下玉米幼苗生长及抗氧化酶基因表达的影响。结果表明,与对照相比,150 mmol/L的NaCl处理使玉米幼苗的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性分别降低了24.09%、12.24%和34.19%,叶绿素含量、可溶性蛋白、可溶性糖和脯氨酸含量分别下降了32.73%、23.71%、13.18%和36.97%,且都达到显著水平,丙二醛(MDA)和质膜透性分别增加了101.98%和68.67%。添加1.0μmol/L MeJA在一定程度上可以缓解盐胁迫对玉米幼苗的损伤,与盐胁迫处理相比,玉米幼苗的SOD、POD、CAT活性分别增加41.33%、26.09%和18.55％,叶绿素含量、可溶性蛋白、可溶性糖和脯氨酸含量分别上升18.97%、58.64%、12.20%和49.81%,丙二醛含量下降了20.50%。外源茉莉酸甲酯能够提高盐胁迫下玉米幼苗的光合性能,与单独盐胁迫处理相比,其净光合速率(Pn)、气孔导度(Gs)、以及蒸腾速率(Tr)分别增加了62.91%、50.14%和69.63%；胞间二氧化碳浓度(Ci)却下降了14.23%,最大光化学效率Fv/Fm、实际光化学效率(ΦPSII)和光化学猝灭系数(qP)分别增加了42.45%、20.96%和33.77%,非光化学猝灭系数(NPQ)下降了12.18%。SOD3、POD3、CAT1三种抗氧化酶基因表达量也显著增加,表明外源茉莉酸甲酯能够有效缓解玉米的盐胁迫损伤。

A pot experiment was conducted to study the effects of exogenous MeJA on the growth of maize seedlings and the expression of antioxidant enzyme genes under salt stress. The results showed that, compared with the control, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of maize seedlings decreased by 24.09%, 12.24% and 34.19% respectively under 150 mmol/L NaCl treatment.The content of chlorophyll, soluble protein, soluble sugar and proline decreased by 32.73%, 23.71%, 13.18% and 36.97% respectively, and all reached significant levels.The content of MDA and plasma membrane permeability increased by 101.98% and 68.67% respectively. Adding 1.0 μ mol / L MeJA could alleviate the damage of maize seedlings under salt stress.Compared with the salt stress treatment, the activities of SOD, POD and CAT increased 41.33%, 26.09% and 18.55% respectively.The content of chlorophyll, soluble protein, soluble sugar and proline were increased by 18.97%,58.64%,12.20% and 49.81% respectively.The content of MDA decreased by 20.50%. Net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) increased by 62.91%, 50.14% and 69.63% respectively, intercellular CO2 concentration (Ci) decreased by 14.23%.Maximum photochemical efficiency(Fv/FM), actual photochemical efficiency (ΦPSII) and photochemical quenching coefficient (qP) increased by 42.45%, 20.96% and 33.77% respectively, non photochemical quenching coefficient (NPQ) decreased by 12.18%.The expression of SOD3, POD3 and CAT1 genes also increased significantly. It shows that exogenous methyl jasmonate can effectively alleviate the damage of maize under salt stress.

甘肃省高等学校创新(2020A-053)；甘肃农业大学青年导师(GAU-QDFC-2019-01)作者简介王芳(1980-),女,甘肃民勤人,副教授,博士,主要从事玉米抗逆机理方面的研究。E-mail：wangfang@gsau.edu.cn