3种木本植物在铅锌和铜矿砂中的生长及对重金属的吸收

Growth and metal uptake of three woody species in lead/zinc and copper mine tailing

通过盆栽试验评价3种木本植物紫穗槐、桤木和黄连木修复铅锌矿和铜矿尾矿的潜力。结果表明,150d后3种植物在矿砂中都能生长,其中黄连木在铅锌矿砂中生长受到明显抑制,桤木的叶绿素含量显著降低。3种植物的根系发育在2种矿砂中没有受到显著抑制。重金属在3种植物组织中的含量为17.66—55.36 mg/kg(铜)、2.67—196.00 mg/kg(铅)、58.93—333.67(锌,铅锌矿砂)和49.20—199.33(锌,铜矿砂)。3种植物的生物富集系数(BCF)和转移系数(TF)值都小于1。60d后,桤木和黄连木叶片的叶绿素荧光参数与对照相比没有显著变化,PSⅡ的最大量子产量有下降的趋势。重金属胁迫后显著增加Mg、Fe、Cu在功能叶的含量,显著地降低Mn的含量。因此可利用固氮植物紫穗槐在尾矿区造林和修复。

Mine tailings are known to have environmental perniciousness due to their high concentrations of heavy metals.Phytoremediation can provide a cost-effective,long-lasting and aesthetic solution for the reclamation of mine tailings.However,revegetation on mine tailing areas is a difficult practice because of toxicity of heavy metals and low nutrient levels.As a result,most tailings disposal sites are devoid of vegetation.Hence,plant species with barren tolerance and excess metal tolerance are required.To date,most of studies focused on the potential utilization of grasses in revegetation.Few studies have evaluated the potential of fast growing woody species for revegetation and remediation of mine tailing areas.The objectives of this study were to reveal the adaptation of the selected woody plants to mine tailings and the potential use of woody species for the revegetation of mine tailings areas in China.A greenhouse pot experiment was conducted to evaluate the potential of woody plants for revegetation in copper（Cu） and lead/zinc（Pb/Zn） mine tailings.Three woody plants species（Amorpha fruticosa Linn,Alnus cremastogyne and Pistacia chinensis） were tested to assess their growth,chlorophyll content,chlorophyll fluorescence parameters,root morphology,metal accumulation and translocation in plants.Pb/Zn tailings and Cu tailings contained elevated concentrations of total Pb,Zn and Cu,which imposed stress to species planted.All three species can grow in both Cu tailings and Pb/Zn tailings and show different tolerance to stress of tailings.The N fixing shrub A.fruticosa is the most tolerant species to both tailing areas.P.chinensis was significantly stressed in term of plant growth in Pb/Zn tailing.Heavy metals significantly decreased chlorophyll content of A.cremastogyne.The root morphology parameters of all plants grown in tailings showed no difference from that grown in soil.Despite the high concentrations of heavy metals in the mine tailing,there was a slight transfer of these elements to the aboveground biomass.The accumulated metal contents in the plants varied among species from 58.93 to 333.67（for Zn which grown in Pb/Zn tailing area）,49.20 to 199.33（for Zn which grown in Cu tailing area）,2.67 to 196.00（Pb） and 17.66 to 55.36 mg/kg（Cu）.All plant species have low bioconcentration factor（BCF） and translocation factor（TF） except TF value of Zn（TF=0.84 in Cu tailing areas） of P.chinensis.At day 60,the chlorophyll fluorescence parameters of A.cremastogyne and P.chinensis in two tailings showed no difference compared with control,but the quantum yield of PSⅡphotochemist showed the downward trend.The contents of iron（Fe）,magnesium（Mg） and copper（Cu） in leaves increased while manganese（Mn） decreased in A.cremastogyne and P.chinensis grown in tailings than that in control soil.The N-fixing species,A.fruticosa which have the highest tolerance and biomass production,respectively,have great potential application in revegetation in tailings of southern China.