中国莲（Nelumbo nucifera）幼苗抗氧化系统对砷胁迫的响应

为了研究中国莲（Nelumbo nucifera）抗氧化系统对砷胁迫的响应，研究比较了两种不同价态无机砷As（Ⅲ）和砷As（V）对中国莲幼苗可溶性蛋白含量、丙二醛（MDA）含量以及抗氧化系统的影响。结果表明，中国莲幼苗中MDA和可溶性蛋白质含量随砷浓度的增加呈现先升高后降低的趋势。中国莲幼苗的MDA和蛋白质含量受As（V）的影响不如As（11]）敏感。抗氧化系统酶中，超氧化物歧化酶（SOD）对砷处理最敏感，当As（11I）浓度在2．5pmol／L和As（V）浓度在100μmol／L时，SOD酶活性显著高于对照组。过氧化物酶（POD）在As（Ⅲ）处理浓度为10umol／L时就出现显著上升，相对而言，过氧化氢酶（CAT）对As（V）比较敏感。实验结果表明，随着浓度的增加，砷对幼苗产生的氧化胁迫导致SOD、CAT和POD三种酶活性有所增加，以配合清除细胞内的活性氧自由基（ROS），维持细胞代谢的稳定。本研究为进一步研究砷胁迫下莲的生理和生长变化、以及莲的培育和移植提供了部分基础数据。

Responses of the Antioxidant System in Nelumbo nucifera Seedlings to Arsenic Toxicity

To study the antioxidant system of Nelumbo nucifera seedlings in response to arsenic stress, compared the influence of two valences of inorganic arsenic, As （]]]） and As （V）, on soluble protein content, malondialdehyde（MDA）and the antioxidant system. Results showed that： MDA and soluble protein content of N. nucifera seedlings increased and then decreased with increasing concentration; MDA and protein content were more sensitive to As（I]1）than to As （V） treatment. The Superoxide Dismutase（SOD）was the most sensitive to arsenic treatment; when the concentration of As （III）was 2. 5μmol/L and As（V）was 100 μmol/L, the activity of SOD increased significantly. When the concentration of As（III） was 10 μmol/L, the activity of Peroxidase（POD） increased significantly. The Catalase（CAT）was more sensitive to As（V）. From the experimental results, with the increase in arsenic concentration, the enzyme activities of SOD, CAT and POD increased, which can be used to eliminate reactive oxygen species （ROS） and maintain cell metabolism stability. This study provides some basic data for further study of N. nucifera physiology and growth change, cultivation and transplants with arsenic stress.