藤本植物中具镉超积累特征植物的筛选

目的]筛选出对重金属镉(Cd)具有强富集作用的植物,以修复被镉污染的土壤。方法]以湖南常见的25种藤本植物为参试样本,采用室内水培和室外盆栽相结合的方法,设置不同浓度的重金属镉溶液处理参试植株当年生扦插苗,定量测定供试植物根部、茎部和叶片三部分的镉含量及生物量,分析参试植物对重金属镉的耐性和富集特性。结果]水培筛选试验表明:蔓长春花对Cd污染的耐性较强,转移系数和富集系数均大于1,具备了镉超富集植物的基本特征。盆栽浓度梯度试验结果表明:当土壤中Cd投加浓度为25、50 mg kg-1时,蔓长春花地上部分生物量没有明显下降,且地上部分Cd含量均大于其根部,叶片中Cd含量均大于Cd超积累植物应达到的临界含量标准(100 mg·kg-1)。结论]从25种参试植物中筛选出的蔓长春花具有重金属镉超富集植物的基本特征,是一种新的镉超积累植物,建议在重金属镉污染土壤中进一步测试。

Selection for Cd-hyperaccumulator Plant from 25 Lianas Species

Objective] To select the cadmium (Cd) -hyperaccumulator plant for remediating the soil polluted by Cd. Method] 25 lianas species were sampled in Hunan Province, China. The method of indoor hydroponics and outdoor pot experiment were designed. The Cd content from root, stem and leaf were analyzed by quantitative analyzing. Result] The results showed that Vinca major had stronger tolerance to Cd, and both the enrichment coefficient and transfer coefficient were higher than 1 and provided with the basic characteristics of Cd-hyperaccumulator plant in water cultivation. In pot experiment, the aboveground biomass was not significant reduced and the Cd content was higher than underground when the concentration of Cd in soil was 25, 50 mg·kg^-1, respectively, meanwhile, the cumulant ability reached to the standard of 100 mg kg^-1 in leaf. Conclusion] V. major is a species for Cd hyperaccumulator, deeply further test should be carried out.