Cu-Pb-Zn复合污染对宿根花卉植物Sn富集特性的影响

Effects of combined Cu-Pb-Zn contaminants on Sn tolerance and accumulation in perennial flowers

为探明锡矿开采区植物复合污染的生态效应,以宿根花卉植物玉簪(Hosta plantaginea Aschers)和金鸡菊(Coreopsis basalis)为对象,采用土培盆栽试验,对单一及复合污染条件下植物对Sn的吸收积累进行深入剖析。结果表明:单一Sn污染条件下,随Sn浓度升高,两种植物的生长均受到抑制,生物量逐渐减少。当Cu-Pb-Zn复合污染时,较低Sn浓度下,Sn与Cu-Pb-Zn复合污染物产生的拮抗效应抑制了Sn对玉簪和金鸡菊的毒性;较高Sn浓度下,Sn与Cu-Pb-Zn复合污染物产生的协同效应增加了Sn对金鸡菊的毒性。Cu-Pb-Zn复合污染提高了土壤中可生物利用的Sn含量,使玉簪和金鸡菊中富集的Sn含量增加,同时也使玉簪和金鸡菊转移Sn的能力增强。在Cu-Pb-Zn复合污染胁迫下,玉簪和金鸡菊体内富集Cu、Pb和Zn的浓度顺序为Zn>Pb>Cu。随着土壤中Sn浓度的增加,玉簪和金鸡菊对共存的3种重金属的富集量也相应增加,且对共存重金属的转移系数产生了较大影响。金鸡菊由于根部肥大、须根多,与土壤接触面广而对重金属的富集能力高于玉簪。研究表明,共存重金属污染物改变了Sn在宿根花卉植物体内的富集和转移能力,同时Sn的存在也改变了共存重金属污染物在宿根花卉植物体内的富集能力。

In this study,Hosta plantaginea Aschers and Coreopsis basalis,two perennial flowers,were chosen to explore the ecological interactions and effects of combined heavy metal contaminants in a Sn mining field.Soil-culture experiments were performed to test the Sn tolerance and accumulative characteristics of the chosen perennial flowers.Results showed that the growth of the two plants was inhibited(presented as a reduction in biomass)with increasing Sn concentration in soil contaminated only with Sn.The toxicity of Sn contamination was relieved to some extent when combined with Cu-Pb-Zn contamination.The addition of combined Cu-Pb-Zn contaminants increased the amount of bioavailable Sn in the soil,which led to increased Sn accumulation in the two plants studied.Meanwhile,the ability of Sn to translocate to the two plants was also enhanced.Generally,combined Cu-Pb-Zn contaminants accumulated in the plants following the order of Zn>Pb>Cu.The ability of the combined heavy metal contaminants to accumulate and translocate showed a positive correlation with Sn concentration in the soil.The hypertrophic and profuse root system of Coreopsis basalis plants allowed them to have broad contact with the soil,and thus,accumulate a relatively greater amount of heavy metals than Hosta plantaginea Aschers.The results of this study suggest that combined heavy metal contaminants affect the ability of Sn to accumulate and translocate in perennial flowers,and vice versa.