广西荔浦锰矿废弃地植被及优势植物重金属生物蓄积特征

通过对广西荔浦锰矿废弃地植被的调查,共记录到高等植物32种,隶属31个属,18个科。优势植物包括马唐、蕨、白茅、井栏边草、地桃花、商陆、加拿大飞蓬、石山桂花和板栗等九种。对土壤和植物的Fe、Mn、Cd、Pd和Cu等重金属分析结果表明,土壤中的Fe和Mn最高含量分别达到140221mg.kg-1和12114mg.kg-1。优势植物的分布与土壤中Fe和Mn的含量有关,井栏边草分布区土壤中的Mn含量最高,白茅分布区土壤中Mn含量最低;Fe含量最高的土壤为地桃花分布区,最低为白茅分布区。优势植物对Fe和Mn的生物积累特征表现出较大的差异。加拿大飞蓬和马唐有较强的扩散能力,对Mn也有较高的抗性,可作为锰矿废弃地植被重建的先锋物种;商陆和板栗对Mn有较强的富集能力(叶片锰含量分别达3280mg.kg-1和2510mg.kg-1),可用于Mn污染土壤的植物修复。

BIOACCUMULATION OF HEAVY METALS BY DOMINANT PLANTS GROWING IN LIPU MANGANESE MINE, GUANGXI, CHINA

According to recent vegetation survey,in the Lipu manganese mine there were 32 species of higher plants that belong to 31 genera and 18 families,including 9 dominant species: Digitaria sanguinalis,Pteridium aquilinum,Imperata cylindrical,Pteris multifida,Malvastrum coromandelinum,Phytolacca acinosa,Erigeron Canadensis,Osmanthus fordii and Castanea henryi.The analytical results of Fe,Mn,Cd,Pd and Cu in soils and plants indicated that the highest contents of Fe and Mn in soils reached 140221 mg.kg-1 and 12114 mg.kg-1,respectively.The distribution of the dominant species was related to Fe and Mn contents in soils.Pteris multifida grew in the soil with the highest Mn concentration,Urena lobara in the soil with the highest Fe concentration,and Imperata cylindrica in the soil with the lowest Mn and Fe concentrations.The bioaccumulation character of Fe and Mn by different dominant species showed a great diversity.E.canadensis and D.sanguinalis are the possible pioneer plants for the revegetation in manganese mining wastelands because of their rapid growing and strong resistance to Mn contamination.P.acinosa and C.henryi can be used as potential species for phytoremediation of Mn-contaminated soils due to their high capability of enriching Mn.