不同强化剂强化德国景天提取土壤镉和铅研究

Comparison of the Effects of Different Enhancing Agents on Uptake and Transfer of Cd and Pb by Sedum hybridum in the Contaminated Soil

为提高超富集植物对土壤中镉(Cd)、铅(Pb)污染物的植物提取效率,以德国景天为研究对象,通过盆栽试验,研究了6种化学强化剂:鼠李糖脂生物表面活性剂(Rha)、乙二胺二琥珀酸(EDDS)、聚丙烯酸(PAA)、聚丙烯酸接枝腐殖酸(PAA-HA)、植物调节剂增产胺(DCPTA)、增产胺接枝氯化胆碱(DCPTA-ChCl)强化德国景天提取农田土壤Cd和Pb的效果,并考察不同强化剂对土壤重金属Cd、Pb形态的影响。结果表明,6种添加剂处理均能促进德国景天根部对Cd的吸收,DCPTA、DCPTA-ChCl、PAA、PAA-HA处理对德国景天地上部分Cd的吸收表现为促进作用,而Rha和EDDS抑制了Cd从根部向地上部分的转移。PAA-HA对德国景天根部吸收Pb的促进作用最为显著,对应的吸收提高率为51.7%。德国景天对Cd和Pb的富集系数(BCF)范围为3.96~4.83和0.11~0.19,转移系数(TF)为2.19~3.05和0.19~0.39,属于Cd超富集植物。德国景天修复重金属污染土壤中,聚丙烯酸类添加剂、增产胺类生长调节剂有效促进了德国景天对Cd和Pb的吸收富集,在土壤重金属污染植物修复中具有很好的应用潜力。

At present,enhancing heavy metal accumulation in hyperaccumulator has been a hot topic.One of the most promising technologies to increase the efficiency of phytoremediation is the use of enhancing agents.The key of the technology is to choose suitable agents and the combining-hyperaccummulator.In this study,the effects of six different enhancing agents on the remediation of cadmium(Cd) and lead(Pb) contaminated soil by Sedum hybridum in pot experiments were investigated.The enhancing agents were as follows:rhamonolipid(Rha),ethylenediamine dissuccinic acid(EDDS),polyacrylic acid(PAA),polyacrylic acid grafted with humic acid(PAA-HA),plant growth regulator:diethylaminoethyl-3,4-dichlorophrylether(DCPTA) and diethylaminoethyl-3,4-dichlorophrylether grafted with Choline Chloride(DCPTA-ChCl).Effects of enhancing agents on Cd and Pb speciation in soil were also studied.The results showed that all these six kinds of agents promoted Cd uptake by Sedum hybridum root.DCPTA,DCPTA-ChCl,PAA and PAA-HA promoted Cd uptake by the shoot parts of Sedum hybridum compared to the control.However,Rha and EDDS decreased root Cd translocation into the shoot parts of Sedum hybridum.PAA-HA was more effective at contributing to Pb uptake by Sedum hybridum root,and the corresponding absorption improvement rate is 51.7%.Cd and Pb enrichment factor(BCF) of Sedum hybridum were in the range of 3.96-4.83 and 0.11-0.19,respectively.Cd and Pb translocation factor(TF) of Sedum hybridum were in the range of 2.19-3.05 and 0.19-0.39,respectively.Sedum hybridum was further validated as a Cd hyperaccumulating plant species.The results suggest that PAA and plant growth regulator DCPTA has also been demonstrated to promote plant growth,enhancing Cd and Pb uptake by Sedum germanica.The above findings may be essential for understanding the characteristics of heavy metals hyperaccumulation in plants and selection of excellent candidates of enhancing agents for phytoremediation of heavy metal from contaminated soils.