铅胁迫对姜叶片活性氧代谢的影响

Effects of Pb Stress on Reactive Oxygen Metabolism in Ginger Leaves

以‘莱芜大姜'为试材,采用污灌方式研究不同水平铅(Pb)胁迫(土壤Pb含量分别为0、150、450和1350 mg·kg^(-1))对姜叶片活性氧代谢的影响。结果表明,随Pb胁迫水平的升高及胁迫时间的延长,姜叶片中生成速率和H_2O_2含量显著升高,但过度Pb胁迫则使其降低,而丙二醛(MDA)含量和电解质渗漏率则持续增加。Pb胁迫40 d时,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)、抗坏血酸过氧化物酶(APX)、单脱氢抗坏血酸还原酶(MDHAR)、脱氢抗坏血酸还原酶(DHAR)等抗氧化酶活性随Pb胁迫水平的升高显著增强,还原型抗坏血酸(AsA)、总抗坏血酸(AsA+DHA)及还原型谷胱甘肽(GSH)、总谷胱甘肽(GSH+GSSG)等抗氧化物质含量显著升高,AsA/DHA、GSH/GSSG比值显著增加;随胁迫时间的增加,抗氧化酶活性及抗氧化物质含量则多以150 mg·kg^(-1)的轻度Pb胁迫的较高,过度的Pb胁迫则使其显著降低,表明AsA-GSH循环遭受严重破坏。

The effects of the different Pb content（0,150,450,1 350 mg·kg（-1）） stress on the active oxygen metabolism in ginger leaves were studied with a ginger（Zingiber officinale Roscoe） cultivar ＇Laiwu Ginger＇ by using the method of sewage irrigation.The results showed that with the increase of Pb stress level and exposure duration,productivity rate and H_2O_2 content increased significantly and then decreased under excessive Pb stress,while MDA content and electrolyte leakage rate increased continuously.After 40 days of Pb stress which was during the seedling stage,with the increase of Pb stress level,the activities of superoxide dismutase（SOD）,peroxidase（POD）,catalase（CAT）,glutathione reductase（GR）,ascorbate acid（APX）,monodehydroascorbate reductase（MDHAR）and dehydroascorbate reductase（DHAR） were enhanced markedly,and the contents of reduced ascorbic acid（AsA）,total ascorbic acid（AsA＋DHA）,reduced glutathione（GSH） and total glutathione（GSH＋GSSG） were increased remarkably,and the ratios of AsA/DHA,GSH/GSSG were also increased significantly.Moreover,with ginger growth going on and the stress time increasing significantly,the antioxidant enzymes activities and the antioxidant substance contents were higher mostly under 150 mg·kg^（-1） mild Pb stress and inhibited under excessive Pb stress,which indicated that the AsA-GSH cycle suffered serious damage.