两种生物型芦苇胚性悬浮培养物对渗透胁迫的生理响应 Ⅱ．抗氧化酶类活性的变化

渗透胁迫处理下，沙丘芦苇和沼泽芦苇培养细胞的H2O2含量变化不大，MDA含量随时间延长而降低。抗氧化酶中，沙丘芦苇的SOD、CAT、POD和APx的活力均显著高于沼津芦苇，显示出比沼泽芦苇更强的ROS清除能力。胁迫初期（0．5h-1d)沙丘芦苇细胞中主要表现出SOD、CAT活力的提高，胁迫2d后4种酶活力均明显被诱导。两种生态型芦苇的PEG适应性培养物APx及SOD酶活力显著提高，POD活性仅沼泽芦苇中升高。提示SOD、CAT主要参与沙丘芦苇在渗透胁迫下的短期响应，而APx与长期响应有关。

Responses in suspension cultures of two ecotypes of reed (Phragmites communis) under osmotic stressII . Changes of the reactivity of anti-oxidative enzymes

The changes of contents of H2O2,MDA and activities of several anti-oxidative enzymes such as SOD,POD,CAT and APx in the suspension cultures of two reed ecotypes-dune reed and swamp reed-under osmotic stress mediated by 20% PEG-8000 were analyzed in this work. The results showed that the content of H2O2 changed little while that of MDA decreased along the time course in the cells of both reed ecotypes under stress. The activities of SOD,CAT,POD and Apx were significantly higher in dune reed than in swamp reed under stress thus suggested that dune reed possessed stronger potential of eliminating ROS. The dune reed mainly improved the activities of SOD and CAT during the early stage of treatment (0. 5 h-1 d) and did not significantly improve the activities of APx and POD until 2 days later. In the acclimated suspension culture of both reed ecotypes,Apx was greatly induced. These results suggested that SOD and CAT were mainly related to the short-term response and Apx was responsible for the long-term response.