中文摘要：

还原型谷胱甘肽（GSH）和谷胱甘肽转硫酶（GST）是水稻解毒系统中的重要组成部分。采用水培法研究了耐性不同的两种水稻（特优559和K优818）在不同程度镉（Cd）胁迫下GSH和GST的变化情况。结果表明，Cd处理导致两种水稻生物量减少、Cd吸收积累增加，水稻根部Cd含量和积累量均高于地上部，但Cd从水稻根部向地上部的转运存在明显的种间差异，耐性较弱的特优559的cd转移率（S/R）随处理cd浓度提高而上升，而耐性较强的K优818则恰好相反，将cd更多地钝化在根部。两种水稻GSH和GST的变化趋势也有所不同，Cd胁迫使特优559的GSH含量和GST活性显著增加，而K优818的GSH在低浓度cd处理时出现了小幅下降，但其GST活性变化与特优559相似，根部增幅更为显著。以上结果说明，水稻GSH和a孵在cd解毒和钝化过程中发挥了重要的作用，而且其应答机制存在着一定的基因型差异，这可能与两品种GST同功酶的组成、表达和功能不同有关。

英文摘要：

Reduced glutathione（GSH） and glutathione S-transferase（GST）are important components in the defence system of plants. The conjugation of GSH to a variety of cytotoxic substances is catalyzed by GST. However, the function of GST in the detoxification of heavy metal stress is not well understood. In this study, two rice cuhivars （Teyou 559 and Kyou 818 ）with different Cd tolerance were hydroponically cultured to study the variation of GSH and GST under different Cd treatments（0, 5 and 20 mg·L-1）. It was shown that Cd treatment reduced the biomass and increased Cd uptake and accumulation of two rice cultivars. Cadmium content and accumulation in rice roots were higher than those in shoots. However, Cd translocation from roots to shoots differed significantly between the two cultivars. The ratio of Cd concentration in shoots over roots （S/R）inereased for the less tolerant Teyou 559 but decreased for the more tolerant Kyou 818 when more Cd was added in the solutions. The variation of GSH content and GST activity also differed for the two cultivars. Cadmium stress significantly promoted GSH and GST in Teyou 559. However, the GSH content of Kyou 818 slightly declined under the low Cd treatment. Nevertheless, its GST activity changed with the similar trend with Teyou 559, and it increased more significantly in roots. The above results revealed that rice GSH and GST play important roles in Cd detoxificatian and immobilization, and their response mechanisms also exhibited genotypic differences, which may be related to the difference in composition, expression and function of GST isoenzymes in the two rice cultivars.