中文摘要：

以番茄（Lycopersicom esculetrtum Mill．）果肉及种子为试材，研究了活性氧（O2^-和H2O2）及抗氧化酶（SOD、CAT、GR、APX）活性在果实成熟衰老过程中的变化。结果表明，在果实成熟衰老过程中，种子中O2^-产生速率及H2O2含量显著高于同时期的果肉，且H2O2含量在粉红期后大幅度增加。种子中SOD、CAT、GR活性高于同时期的果肉，APX活性则无显著差异。果实成熟初期CAT活性随H2O2的积累逐渐增强，果实成熟后期CAT活性急剧下降，APX及GR仍具有一定活性。种子MDA含量峰值出现早于果肉，且峰值是果肉中的1．5倍。种子中活性氧的产生能力高于果肉，种子中高浓度的活性氧含量可能与果实的成熟衰老过程有关，H2O2可能是启动果实衰老的一个重要因子。

英文摘要：

Tomato （Lycopersicom esculentum Mill. ） pericarp and seed were used to investigate the changes of reactive oxygen and activities of antioxidant system enzymes during fruit ripening and senescence. Superoxide production rate （O2^-）, hydrogen peroxide （H2O2 ） content and the activities of superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX） and glutathione reductase （GR） were determined. The degrees of the oxidative damage to the membrane lipids （MDA content） were also examined. The results showed that O2^- production rate and H2O2 content in seed were significantly higher than those in pericarp at all maturity stages, and the H2O2 content in the seed increased sharply after the pink stage. Higher activities of SOD, CAT and GR were observed in the seeds than in the pericarp. Higher APX activities were found from the BR stage to the RED stage in seed and that in pericarp. At the beginning of fruit ripening, an increase of CAT activity followed the accumulation of H2O2, but its activity declined quickly by the end of ripening, while that of APX and GR kept partial activities. These patterns of enzyme activity suggest that the AsA-GSH cycle might play an important role in scavenging H2O2. The maximum MDA content appeared in seeds earlier than in the pericarp, the maximum being 1.5 fold of that in the pericarp. High concentration of reactive oxygen in seed might be closely related with fruit ripening, and H2O2 might be an important factor in triggering the senescence.