土壤Pb污染修复植物的耐性及累积特性比较

Pb Tolerance and Accumulation of Pollutant-Remediation Plants

为筛选Pb污染土壤修复植物,在文献调研的基础上,选择禾本科、豆科、菊科和茄科的12种植物作为研究对象,采用室内盆栽试验,进行不同质量浓度(0、500、1 000、1 500、2 000mg·kg^(-1))的Pb胁迫处理。通过分析植物根长、株高、生物量、地上部和地下部Pb含量,比较不同植物对Pb的耐性及累积特性。结果表明:随着Pb处理浓度的增加,12种植物的生物量均呈现下降的趋势且植物Pb积累表现出明显的根系>茎叶的分异特性;通过耐Pb性综合评价,三叶草、黑麦草、早熟禾可作为铅锌矿区耐性栽培植物;在土壤Pb施加浓度为1 500 mg·kg^(-1)时,富集系数大于1的共有6种,依次为:早熟禾(3.46)>三脉紫菀宽伞变种(3.34)>黑麦草(2.32)>狗牙根(1.78)>黑心菊(1.72)>辣椒276(1.26);转运系数大于1的共有3种,依次为:辣椒276(1.36)>黑心菊(1.30)>紫花苜蓿(1.23)。最后综合富集、转运系数及修复潜力指数,得出黑心菊在1 025mg·kg^(-1)时,其地上部铅积累量最高,为2.576mg·株^(-1),具有很好的铅修复潜力,可作为铅超富集植物的先锋物种。

Based on a literature search,12 species in the families of Gramineae,Leguminosae,Compositae and Solanaceae,that are phytoremediation plants capable of decontaminating Pb polluted soil,were studied for their Pb tolerance and accumulation capacities.The plants were subjected to Pb stress at varied concentrations(i.e.,0,500,1 000,1 500 and 2 000 mg·kg-1)in an indoor pot experimentation.The root length,height,biomass,above-and under-ground Pb contents were determined to compare the Pb tolerance and accumulation of the plants.The results showed that,as the Pb concentration in soil increased,all plants decreased on biomass and increased Pb content in the order of roots,stems,and leaves.A comprehensive evaluation suggested that Campsis grandiflora,Lolium perenne and Poa pratensis had the potentials for use of remediating the soil pollution in lead and zinc mining areas.Among the tested,6 plants showed a bioconcentration factor(BCF)greater than 1 at the Pb contamination level of 1 500 mg·kg-1:Poa annua at 3.46,Aster ageratoides at 3.34,L.perenne at 2.32,Cynodon dactylon at 1.78,Rudbeckia hirta at 1.72,and Capsicum annuum 276 at 1.26.And,three varieties had a translocation factor(TF)greater than 1:C.annuum 276 at 1.36,R.hirta at 1.30,and Medicago sativa at 1.23.Taking BCF,TF and repair potential index together into consideration,R.hirta appeared to be the choice species for Pb remediation on polluted soil with a displayed capability of accumulating 2.576 mg Pb per plant in above-ground parts from a soil containing Pb 1 025 mg·kg-1.