GSH对铅胁迫下多年生黑麦草幼苗抗氧化系统的调控

本试验以12周龄的多年生黑麦草（Lolium perenne ‘cuttle’）幼苗为试验材料，用铅（Lead，Pb），Pb+还原型谷胱甘肽（Glutathione，GSH）和Pb+丁硫氨酸-亚砜亚胺（L-Buthionine-sulfoximine，BSO）处理1周，研究GSH对Pb胁迫下多年生黑麦草抗氧化系统的调控机理，寻求缓解植物Pb胁迫的有效措施。结果表明：Pb胁迫下，外源GSH能够显著提高多年生黑麦草Pb的吸收和转运，增加抗氧化酶超氧化物歧化酶（Superoxide dismutase，SOD）、谷胱甘肽过氧化物酶（Glutathione peroxidase，GPX）和谷胱甘肽还原酶（Glutathione reductase，GR）活性，显著增加抗氧化剂GSH含量及GSH/氧化型谷胱甘肽（Oxidized glutathione，GSSG）比率，提高了植物的还原力。外源GSH也能够显著降低活性氧超氧阴离子（Superoxide anion，O₂^·-）和过氧化氢（Hydrogen peroxide，H₂O₂）的产生量、膜的相对透性（Relative electric conductivity，EC）和丙二醛（Malondialdehyde，MDA）含量，保持了细胞的稳定性，减轻了膜脂的过氧化程度。外源BSO作用基本上与GSH相反。相关分析表明：GSH可通过提高SOD和GPX等抗氧化酶的活性，促进GSSG和GSH的相互转化，降低活性氧产生量，提高植物抵抗逆境胁迫的能力。

Effects of Glutathione(GSH)on Antioxidant Defense System of Lolium Perenne Seedlings under Lead Stress

In this study,Lolium perenne seedlings (12 weeks old) were exposed to Pb,Pb+GSH and Pb+BSO treatment for one week to investigate effects of glutathione on antioxidant defense system of leaf and root. The results showed that Pb+GSH treatment increased Pb absorption and transport. It also increased antioxidase activity such as superoxide dismutase(SOD),glutathione peroxidase(GPX) and glutathione reduction(GR),antioxidant GSH content and GSH/GSSG ratio. It enhanced Seedlings' reducing power. On the contrary,the content of ROS(O₂^·- and H₂O₂),malondialdehyde content (MDA) and relative electric conductivity(EC) declined under Pb+GSH treatment. Pb+BSO treatment had almost opposite effects to that of Pb+GSH treatment. The correlation analysis indicated that GSH could reduce reactive oxygen species production and alleviate oxidative stress by increasing antioxidase activity and promoting the mutual transformation of GSSG and GSH.