四种草本植物对铅锌尾矿土壤重金属的抗性与吸收特性研究

盆栽试验的结果表明,高羊茅、早熟禾、黑麦草和紫花苜蓿在铅锌尾矿土壤或处理的尾矿土壤上都能生长,但在处理土壤上生长的植物长势明显优于对照,其中紫花苜蓿的生物量所受影响比其他几种草本植物更大,说明其重金属抗性低于其他几种植物.单位面积上4种植物体内重金属含量均为Zn>Pb>Cu>Cd,但每种植物对Cd、Pb、Zn和Cu的吸收浓度和分布均不相同,一般为根系浓度大于茎叶.加入改良剂和有机肥(菜枯)使生长在铅锌尾矿污染土壤上的4种草本植物生物量显著增加,植物体中的Cd、Pb和Zn元素浓度下降,但Cu元素浓度反而上升,结果单位面积上4种草本植物吸收各重金属元素的量均有所增加,可见利用改良措施与草本植物相结合的方法来修复重金属污染土壤具有可行性.

Resistance and uptake of heavy metals by four herbaceous plants from soil polluted lead/zinc mine tailings

In the study presented in this paper a pot experiment was conducted which showed that four herbaceous plants: Festuca arundinacea,Poa pratensis,Lolium perenne and Medicago sativa,could survive in soil polluted with lead/zinc mine tailings or CaCO_3,organic manure and their mixed substrates.With growth in the soils containing heavy metals poorer than in the latter mentioned treatments.As such,CaCO_3 and organic manure could be used as an ameliorant to improve the growth of plants in soils polluted with mine tailings.The biomass of alfalfa was influenced by heavy metals more severely than the other substrates used, which indicates that alfalfa has a lower resistance to heavy metals.The contents of Cd,Pb,Zn and Cu in the four herbaceous plants were all in the order Zn>Pb>Cu>Cd,but they varied in Cd,Pb,Zn and Cu uptake and distribution.Generally,their concentrations were higher in the roots than in the shoots.CaCO_3 and organic manure reduced the concentrations of Cd,Pb and Zn in the plants while increasing the Cu concentration.On the other hand,increased biomass may raise the uptake rate per unit area.As such,it is feasible to use the method of applying ameliorants and growing herbaceous plants in soil polluted with heavy metals in order to reduce heavy metal contamination.