宝山堇菜多金属吸收特征和耐性策略

宝山堇菜Viola baoshanensis Shu,Liu et Lan是一种Cd超富集植物,但它对不同重金属的吸收和转运能力有待进一步研究。从湖南桂阳宝山多金属矿区中筛选4个宝山堇菜优势分布的小生境,分析这些生境中宝山堇菜及其根区土壤的重金属质量分数。化学分析结果显示,宝山堇菜优势分布土壤中Cd、Pb、Zn、Cu、Mn和Fe的平均质量分数（mg/kg）分别为471、15 044、8 273、1 776、4 702和69 054。宝山堇菜地上部Cd、Pb、Zn、Cu、Mn和Fe的平均质量分数（mg/kg）分别为387、1 077、1 037、99、379和1 812,其中Cd、Pb超过超富集植物标准,Zn、Cu的平均质量分数大约是Zn、Cu超富集植物标准的10%,Mn的平均质量分数低于Mn超富集植物标准的5%,Fe的平均质量分数高于1 000 mg/kg。上述结果表明,宝山堇菜可以超富集Cd和Pb,富集Zn、Cu和Fe以及低积累Mn。此外,宝山堇菜对不同重金属差别化吸收模式可能也代表了超富集植物适应重金属复合污染土壤的一种策略。

Multi-metal uptake properties and tolerance strategies of Viola baoshanensis

Viola baoshanensis is a well-known cadmium（Cd） hyperaccumulator plant,but its ability to absorb and transport different heavy metals is still poorly understood.In the present study,four different habitats dominated typically by V.baoshanensis were in-vestigated in the Baoshan mining area,Guiyang City,Hunan Province.Chemical analysis demosntrated that the total average content（mg/kg） of Cd,Pb,Zn,Cu,Mn and Fe in the rhizosphere soil samples of this plant grown in the four habitats was 471,15 044,8 273,1 776,4 702 and 69 054,respectively.In contrast,the average Cd,Pb,Zn,Cu,Mn and Fe concentrations（mg/kg） in the shoots of V.baoshanensis were 387,1 077,1 037,99,379 and 1 812,respectively.Noticeably,both shoot Cd and Pb concentrations exceeded values considered to be in the hyperaccumulator range for Cd and Pb.Meanwhile,the average shoot Zn and Cu concentrations in V.baoshanensis were approximately 10% of the levels seen in Zn and Cu hyperaccumulator plants,and the average shoot Fe concentra-tion of this plant is also considerably higher than seen in non-accumulator plants（1 812 mg/kg）.However,the average shoot Mn concentration in V.baoshanensis was less than 5% of the typical values seen in Mn hyperaccumulator plants.These results suggest that V.baoshanensis possesses the ability to accumulate and tolerate high levels of multiple metals,and this plant also has the capac-ity to hyperaccumulate Cd and Pb,accumulate high levels of Zn,Cu and Fe,but does not accumulate significant amounts of Mn.In addition,the diversity for the divalent metal uptake by V.baoshanensis in this study might further indicate a potential strategy of metal hyperaccumulator plants for adapting soils polluted with mixtures of different heavy metals