锰渣堆场优势植物对Mn的富集特点及作用机制

Enrichment Characteristics and Mechanism of Mn by Dominant Plants in Manganese Residue Disposal Sites

[目的]对贵州省东部地区两种类型的锰渣堆场(采选渣、电解锰渣)上优势植物的Mn富集特点及作用机制进行分析,旨在为该区域锰渣堆场的生态修复提供理论依据。[方法]在野外调查采样的基础上,对优势植物Mn含量、生长基质总Mn含量和低分子量有机酸提取态Mn含量进行测定。[结果]锰渣堆场上优势植物体内Mn含量介于34.47~680.70 mg/kg之间,且存在着个别植物组织中的Mn含量超过一般植物正常范围的现象,Mn在植株器官中的分布主要表现为:根>叶>茎或枝。优势植物生长基质中的总Mn含量介于20217.14~75115.58 mg/kg之间,总体表现为:根际基质<非根际基质。低分子量有机酸对基质中Mn的提取效率在25.72%~78.30%之间,总体表现为:根际基质>非根际基质。[结论]在植株吸收和根际效应的双重作用下,锰渣堆场优势植物具有治理Mn污染的潜力。

[Objective]The characteristics and mechanism of Mn enrichment of dominant plants in two types of manganese residue disposal sites(manganese mine residue and electrolytic manganese residue)were analyzed,in order to provide useful theoretical information to benefit the ecological restoration of manganese residue disposal sites.[Methods]On the basis of field investigation,Mn content of dominant plants,total Mn content of growth matrix and low molecular weight organic acid extracted Mn content were detected.[Results]Mn content in dominant plants ranged from 34.47 mg/kg to 680.70 mg/kg.Mn content in individual plant tissues exceeded the normal range of general plants.The distribution of Mn in plant organs was as follows:root>leaf>stem or branch.The content of total Mn in the growth matrix of dominant plants ranged from 20217.14 mg/kg to 75115.58 mg/kg,and the rhizosphere matrix was less than that of non-rhizosphere.The extraction efficiency of Mn from matrix by low molecular weight organic acids ranged from 25.72%to 78.30%,and the overall performance was rhizosphere matrix>non-rhizosphere matrix.[Conclusion]Under the dual effects of plant absorption and rhizosphere effect,the dominant plants in manganese residue disposal sites have the potential to control Mn pollution.