【作者】 孙瑞莲；

【导师】 周启星；

【作者基本信息】 中国科学院研究生院（沈阳应用生态研究所） ， 生态学， 2006， 博士

【摘要】 在已发现的超积累植物中,镉超积累植物种类较少,对其重金属耐性及超积累机理的研究还未有突破性进展,这些植物金属耐性机理的描述对于镉污染土壤的植物修复研究是非常有意义的。本研究以镉超积累植物龙葵(Solanum nigrum L.)、球果蔊菜(Rorippa globosa (Turcz.) Thell.)为研究对象,以茄子(Solanum melongena L.)和风花菜(Rorippa islandica (Oeder.) Borb.)为对照植物,描述了镉超积累植物污染耐性的生态特征,系统探讨了镉超积累植物的耐性机制。(1)龙葵较茄子有更高的镉耐性及镉积累性;球果蔊菜较风花菜有更高的镉耐性及镉积累性,球果蔊菜茎部受抑制现象是实现其特异吸收和积累重金属的适应性反应,这种地上部营养物质的重新分配现象可能是球果蔊菜作为超积累植物独特的生态特征。(2)龙葵根系中SOD和CAT活性及叶片中POD和CAT活性的协同作用在缓解镉积累引起的膜脂过氧化损伤中发挥着积极作用,球果蔊菜叶片SOD和CAT的协同作用在缓解镉积累引起的膜脂过氧化损伤中也发挥重要作用,可以推断龙葵、球果蔊菜体内抗氧化酶防御系统在其镉耐性中扮演重要的角色。(3)镉的污染胁迫均能明显促进龙葵和球果蔊菜体内脯氨酸的积累,脯氨酸在其镉耐性及积累性中扮演着重要角色,其中叶片脯氨酸可能发挥着更大的作用。(4)龙葵叶片中柠檬酸和乙酸含量的动态变化与其镉积累有关,球果蔊菜叶片中苹果酸和酒石酸含量的动态变化与其镉积累有关,有机酸可能在龙葵及球果蔊菜镉耐性及积累性中起到一定的作用,但高含量的有机酸并不是植物镉耐性和超积累性的主要原因。(5)植物螯合肽可以作为植物镉超积累特征的生物指标,但植物螯合肽的合成并非镉超积累植物耐性的主要机制。更多还原

【Abstract】 Among the group of the known metal-hyperaccumulators, Cd-hyperaccumulators are relatively scarce. Although remediation of contaminated soils using Cd-hyperaccumulators is regarded as an economic and green method, the lack of understanding basic biochemical, physiological, ecological, and molecular mechanisms involved in Cd-hyperaccumulation has an adverse effect on the optimization of the phytoextraction technique and obstructs its further commercial application. The main aims of this study were to explore ecological characteristics and analyze pollution-tolerance mechanisms of Cd-hyperaccumulators Solanum nigrum L. and Rorippa globosa(Turcz.) Thell., in comparison with a closely related species Solanum melongena L. and Rorippa islandica(Oeder.) Borb..Solanum nigrum was considerably higher tolerant and hyperaccumulative to Cd than S. melongena. Similarly, Rorippa globosa was higher tolerant and hyperaccumulative to Cd than R. islandica. The growth inhibition of R. globosa stems was the unique ecological character as the Cd-hyperaccumulator.The synergism between the activity of SOD and CAT in the roots and the activity of POD and CAT in the leaves of S. nigrum, the synergism between the activity of SOD and CAT in the leaves of R. globosa represent effective defense strategies. Antioxidative defenses in the Cd hyperaccumulator might play an important role in Cd tolerance.The stress of Cd pollution could significantly increase the level of free proline in S. nigrum and R. globosa. It could be suggested that free proline might play an important protective roles against Cd stress. Free proline in the leaves had the stronger ability than that in the roots. Acetic and citric acids in the leaves of S. nigrum might be related to its Cd hyperaccumulation. Tartaric and malic acids in the leaves of R. globosa might be related to its Cd hyperaccumulation. Organic acids may play an important role in Cd tolerance and hyperaccumulation. High level of organic acids is not likely primary reason of Cd hyperaccumulation and hypertolerance.PCs may be an important biomarker of Cd hyperaccumulation. PCs do not appear to be involved in Cd tolerance in the hyperaccumulators. PCs do not play an important role in Cd tolerance of S. nigrum and R. globosa.更多还原