外源MeJA对高温胁迫下半夏抗氧化系统和胁迫基因的影响

研究叶面喷施外源MeJA对高温胁迫下半夏的超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)活性的影响;对脯氨酸(Pro)、丙二醛(MDA)、可溶性糖含量及有效成分含量的影响;对小分子热激蛋白(sHSP)等胁迫相关基因表达的影响。将生长状况一致的半夏植株在40℃高温下进行胁迫处理,实验组喷施50μmol·L^-1的外源MeJA溶液,空白组喷施等量的水,分别在处理2、6、12、24、48 h时进行取样,对样品进行指标测定。结果发现,在40℃高温下,喷施一定浓度的外源MeJA可以提高半夏叶片的SOD、POD、APX活性,降低MDA质量分数,增加脯氨酸及可溶性糖含量;对半夏有机酸含量无明显影响。2个细胞质型小分子热激蛋白和GRRBP蛋白,在MeJA处理后表达量显著增加。由此得出结论:喷施外源MeJA可以增强半夏中部分抗氧化酶的活性,保护半夏的细胞膜,增强细胞的渗透调节能力,且外源MeJA可能增加半夏高温胁迫响应基因的表达。

Effects of Exogenous MeJA on Antioxidant System and Stress Genes of Pinellia ternata under High Temperature Stress

We studied the effects of exogenous MeJA on the activities of superoxide dismutase(SOD),peroxidase(POD)and ascorbic acid peroxidase(APX)of Pinellia ternata under high temperature stress,effects on proline(Pro),malondialdehyde(MDA),soluble sugar content and active ingredient content,and the effect on the expression of stress-related genes such as small molecule heat shock protein(sHSP).The P.ternata plants with consistent growth status were subjected to stress treatment at 40℃,the experimental group was sprayed with 50μmol/L exogenous MeJA solution,and the blank group was sprayed with the same amount of water.Samples were taken at 2,6,12,24 and 48 h of treatment,respectively,and the indexes of the samples were determined.The results showed that spraying exogenous MeJA at a certain concentration at 40℃could improve SOD,POD and APX activities of P.ternata leaves,reduce MDA content and increase proline and soluble sugar content.There was no obvious effect on the organic acid content of P.ternate.The expression levels of 2 cytoplasmic small molecule heat shock proteins and GRRBP proteins increased significantly after MeJA treatment.Therefore,spraying exogenous MeJA can partially enhance the activity of antioxidant enzymes in P.ternate,protect the cell membrane of P.ternate,and enhance the osmotic adjustment ability of cells.Moreover,exogenous MeJA may increase the expression of P.ternate high temperature stress response genes.