不同改良剂对镉铅矿渣赤桉根际真菌群落结构及功能类群的影响

Effects of different amendments on fungal community structure and functional groups of Eucalyptus camaldulensis rhizosphere in Cd and Pb tailings

基于Illumina高通量测序技术和FUNGuild平台,探究4种改良剂(有机菌肥、有机肥、无机肥和菌剂)联合赤桉修复对Cd、Pb矿渣基质理化性质、不同形态Cd和Pb比例、真菌群落结构和真菌功能类群的影响,分析调控真菌群落结构变化的主导环境因子。结果表明,有机肥、有机菌肥联合赤桉修复均能显著提高矿渣基质pH值、阳离子交换量和残渣态Pb的比例,显著降低可还原态Pb的比例。高通量测序结果表明,改良剂联合赤桉修复可显著改变基质真菌群落结构,增加伞菌纲的相对丰度,降低粪壳菌纲的相对丰度。功能类群分析表明,有机肥、有机菌肥联合赤桉修复增加土壤腐生真菌的相对丰度,减少植物病原菌的相对丰度;无机肥和菌剂联合赤桉则减少土壤腐生真菌的相对丰度,增加植物病原菌的相对丰度。相关性分析和Mantel检验表明,阳离子交换量、pH值和不同形态Pb比例是影响基质真菌群落的关键因子。上述结果表明,添加有机肥和有机菌肥联合赤桉修复可提高Cd、Pb矿渣基质pH值和阳离子交换量,降低Pb的生物毒性,改变真菌群落结构,增加土壤腐生真菌比例,减少植物病原菌,是生态安全的联合修复方法。

To clarify the remediation effects of four amendments(bacteria-based organic manure,organic manure,inorganic fertilizer and bacterial agent)separately combined with Eucalyptus camaldulensis planting on Cd and Pb tailings,we examined physicochemical properties and the proportions of different forms of Cd and Pb in the tailings.Fungal community structure and functional groups were analyzed based on Illumina high-throughput sequencing technology and FUNGuild platform.The dominant environmental factors regulating fungal community structure were analyzed.The results showed that organic manure and bacteria-based organic manure combined with E.camaldulensis significantly increased pH,cation exchange capacity and the proportion of residual Pb while significantly decreased the proportion of reducible Pb.The high-throughput sequencing results showed that the four amendments significantly changed fungal community structure,increased the relative abundance of Agaricomycetes and reduced that of Sordariomycetes in tailings when combining with E.camaldulensis.Functional group analysis results showed that,when combining with E.camaldulensis,organic manure and bacteria-based organic manure increased the relative abundance of soil saprotroph and reduced that of plant pathogen.By contrast,inorganic fertilizer and bacterial agent reduced the relative abundance of soil saprotroph and increased that of plant pathogen.The results of correlation analysis and Mantel test showed that cation exchange capacity,pH,and the proportion of different forms Pb were the key factors affecting fungal community structure.Our results suggest that organic manure and bacteria-based organic manure combining with E.camaldulensis can increase pH and cation exchange capacity,reduce the biological toxicity of Pb in tailings,change the fungal community structure,increase the proportion of soil saprotroph,and reduce plant pathogens.These two amendments are ecologically safe methods for the remediation of Cd and Pb tailings.