中华山蓼对重金属Cu胁迫的生理响应

Physiological Responses of Oxyria sinensis （Polygonaceae） under Cu2+ Stress

筛选对重金属具有耐受或者富集能力的植物类群对于矿区的生态恢复具有重要的指导意义.利用不同浓度的Cu^2+并结合不同处理时间,通过土培试验研究了采自矿区(东川)和非矿区(丽江)的中华山蓼( Oxyria sinensis )对重金属Cu胁迫的生理响应.结果表明:叶中超氧化物歧化酶含量显著高于根,处理一个月的植株的过氧化物酶含量显著高于处理两个月的植株,根和茎的过氧化物酶含量显著高于叶.根和茎的蛋白质含量显著高于叶,但丙二醛含量不存在显著性差异.此外,处理一个月植株的游离脯氨酸、叶绿素和Cu^2+含量均显著高于处理两个月的植株,而来自东川的植株的叶绿素含量显著高于来自丽江的植株,经过Cu^2+胁迫的样本体内的Cu^2+含量显著高于对照组.结果表明,中华山蓼对Cu胁迫具有一定的耐受性,且来自东川矿区的植株耐受性强于来自丽江非矿区的植株;抗氧化系统中的超氧化物歧化酶和过氧化物酶在实验结果中均出现显著变化,说明这两种酶在提高中华山蓼对重金属Cu的耐受能力方面具有重要的作用.

Screening plant species that are tolerant or adaptive to stress from metals are important to ecological restoration of mined lands. Oxyria sinensis is a dioecious plant that is common in mined lands.In order to explore the tolerance traits of O.sinensis from Cu^2+ stress, O.sinensis was cultivated from mined lands Dongchuan and non-mined lands Lijiang.And subjected the plants to the stress of Cu^2+ in different concentrations and different days.Then physiological responses of O.sinensis were measured,including the contents of SOD,POD,CAT and APX from leaves,stems and roots.The contents of MDA,soluble protein,proline,chlorophyll and heavy metal Cu content in the leaves were also examined.The results showed that the content of SOD in the leaves was significantly higher than that in the roots,and the content of POD of plants subjected to Cu^2+ stress after one month was significantly higher than that after two months.In contrast,the contents of CAT and APX was not affected significantly by sex morphs,treatment duration,source of plant,content of Cu^2+ and organ of plant.In addition,the content of soluble proteins in the roots and stems was significantly higher than those in the leaves,but the content of MDA was not affected significantly.The contents of heavy metal Cu content increased significantly in plants subjected Cu^2+ stress in comparison with control,and the contents of proline,chlorophyll and heavy metal Cu content after one month were significantly higher than that after two months.Conclusively,the results suggest that O.sinensis could be tolerant to Cu^2+ stress,and both SOD and POD of O.sinensis play important roles in coping Cu^2+ stress.Importantly,plants from mined lands were more tolerant to heavy metal Cu than those from non-mined lands,which could be a good support for ecological restoration of mined lands in selecting sources of plant species.