广西典型矿区中植物对Cu、Mn和Zn的富集特征与潜在的Mn超富集植物

Accumulation of Cu,Mn and Zn in plants grown in areas near three abandoned mines in Guangxi and the discovery of potential Mn-hyperaccumulators

本文对广西锰矿区、铅锌矿区和金矿区土壤和植物的重金属含量进行了调查分析。在所调查的24种植物中，Cu含量在30．8～183．8mg／kg范围，Mn含量在143．6～27514mg／kg范围，Zn含量在113．3～1773mg／kg范围。相对于正常条件下生长的普通植物来说，其Cu、Mn和Zn含量都较高。生长在锰矿区的狗牙根、香附子和菜蕨中Mn的含量分别达到27514、16144和11516mg／kg，相应的富集系数为11．4、6．7和4．8。这3种植物均达到Mn超富集植物的相关标准，因此是潜在的Mn超富集植物。

In order to screen the potential hyperaccumulators, the concentrations of Cu, Mn and Zn in 24 dominant plants grown in areas near abandoned Mn, Pb/Zn and Au mines in Nanning City of Guangxi Province were investigated. The results show that most plants contained high concentration of metals resulting from the increased metal concentrations in the soils near the mines. Mn concentration of Mn-mine soil （2415.0 mg/kg）, which was 14.0 times greater than Mn background value of Guangxi soil, was higher than that of Pb/ Zn-mine soil （687.5 mg/kg） and Au-mine soil （487.2 mg/kg）. Most of the investigated plants grown on the Mn mine contained higher concentration Mn in the aboveground tissue （909.0-27514.0 mg/kg） than that （143.6-4388. 0 mg/kg） grown on other mines. Among the plants investigated, three species of plants, Cynodon dactylon, Cyperus rotundus and Callipteris esculenta, grown on Mn-mine could hyperaccumulate Mn in their tissues, with the Mn contents and bioconcentration factors to Mn being 27514.0 mg/kgand 11.4, 16144. 0 mg/kg and 6.7, and 11516.0 mg/kg and 4.8, respectively. The plants investigated grown on Pb/Zn mine contained more Zn （252.8-1571.0 mg/kg） and Mn （143.6-4388.0 mg/kg） than that （113.3-642. 8 mg/kg and 247.1-1940.0 mg/kg for Mn and Zn, respectively） grown on Au mine. The Cu concentration （30.8-183.8 mg/ kg） of the plants grown on the three mines was lower than that of Mn and Zn. The concentrations of Cu, Zn and Mn of food crops grown on the mines were higher than that in normal plants, with potential threats to humans and livestock health. The results indicate that the three plant species, Cynodon dactylon , Cyperus rotundus and Callipteris esculenta, grown on these mines accumulated much higher concentration of heavy metals, and they were discovered to be potential Mn-hyperaccumulators.