4种草对铅锌尾矿污染土壤重金属的抗性与吸收特性

Resistance to and uptake of heavy metals by four herbaceous plants grown in the soil polluted by lead/zinc mine tailings

盆栽试验的结果表明,高羊毛、早熟禾、黑麦草、紫花苜蓿在纯尾矿污染土壤或经处理的尾矿污染土壤上都能生长,但在处理的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坪草更大,说明其重金属抗性低于其他几种植物。单位面积上 4 种植物体内重金属质量分数高低均为 w(Zn)>w(Pb)>w(Cu)>w(Cd),但每种植物对 Cd、Pb、Zn 和 Cu 的吸收质量分数和分布均不相同,一般为根系质量分数大于茎叶。加入改良剂(CaCO3)和有机肥(菜枯)使生长在铅锌尾矿污染土壤上的 4 种草坪草生物量显著增加,植物体中的 Cd、Pb、Zn 质量分数下降,但 Cu 质量分数反而上升,结果单位面积上草坪草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坪草相结合的方法来修复重金属污染土壤具有可行性。

A pot experiment showed that four herbaceous plants, tall Fescue, Kentucky bluegrass, perennial ryegrass and alfalfa could survive in the soil polluted by lead/zinc mine tailings or in this polluted soil treated by CaCO3, organic manure and their mixed sub- strates, but grown in the check soil was poorer than in the treatments, therefore, CaCO3 and organic manure could be used as an am- eliorant to improve the growth of plants in the polluted soil. The biomass of alfalfa was influenced by heavy metals more severely than that of others, which meant that alfalfa was less resistant to heavy metals than other three plants. The contents of Cd, Pb, Zn and Cu in the four herbaceous plants all presented in the order w(Zn) > w(Pb) > w(Cu) > w(Cd), but it varied in Cd, Pb, Zn and Cu uptake and distribution. Generally, their contents were higher in the roots than in the shoots. CaCO3 and organic manure reduced the contents of Cd, Pb , Zn and increased content of Cu in these plants. But increased biomass may raise the uptake rate per unit area. So it is feasible to using this method that applying ameliorants and herbaceous plants to removing heavy metals from the soil.