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目的探讨烯效唑(S3307)对干旱胁迫下薏苡抗氧化酶活性及DNA甲基化水平的影响。方法将薏辽5号种子培养至幼苗的两叶一心期,实验分为3组:对照组(control):用Hoagland培养液处理;干旱胁迫组(PEG):用25%PEG的营养液处理;S3307缓解组(PEG+S3307组):经S3307预处理后,再用25%PEG处理。检测各组幼苗的形态指标(苗高、茎粗、根长、根数)及过氧化物酶(peroxidase,POD)、超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)的活性,同时采用高效液相色谱(HPLC)法测定各组幼苗的DNA甲基化水平。结果经S3307预处理后,幼苗的株高和根长显著降低(P<0.05),茎粗及根冠比显著增加(P<0.05);SOD、CAT和POD抗氧化酶的活性显著升高(P<0.05);幼苗叶片中5-甲基胞嘧啶(5-m C)比例比control组增加了34.29%(P<0.001),增加幅度比PEG组降低了12.99%。结论 S3307可缓解干旱胁迫下薏苡的膜脂过氧化损伤及DNA甲基化水平的上升,具有良好的壮苗作用,为薏苡的抗旱性机理研究奠定了基础。
Objective To investigate the effects of uniconazole (S3307) on antioxidant enzyme activity and DNA methylation level of Job’s tears under drought stress. Methods The seeds of Yiliao No.5 were cultured to two leaves and one heart phase of seedlings. The experiment was divided into three groups: control group: Hoagland medium; drought stress group (PEG): treated with 25% PEG, S3307 remission group (PEG + S3307 group): pre-treated with S3307 and treated with 25% PEG. Morphological indexes (seedling height, stem diameter, root length and root number) and peroxidase (POD), superoxide dismutase (SOD) and catalase CAT) activity was measured. At the same time, the DNA methylation level of each seedling was determined by high performance liquid chromatography (HPLC). Results After pretreatment with S3307, the plant height and root length decreased significantly (P <0.05) and the stem diameter and root / shoot ratio increased significantly (P <0.05). The activities of antioxidant enzymes in SOD, CAT and POD increased significantly P <0.05). The proportion of 5-methylcytosine (5-m C) in seedling leaves increased by 34.29% (P <0.001) compared with that in control group, and the increase rate was 12.99% less than PEG group. Conclusion S3307 can alleviate the injury of membrane lipid peroxidation and the DNA methylation level of Coix lachryma - jobi under drought stress, and has good seedling effect, which lays the foundation for the study of drought resistance mechanism of Coix lachryma - jobi.