【摘要】 为了解稻田土壤微生物对锑(Sb)和砷(As)污染的长期适应机制,本文以贵州省独山半坡锑矿和某锑矿冶炼厂周边稻田土壤为研究对象.采用野外布点和室内分析的方法,利用Illumina高通量测序技术对稻田垂直剖面土壤细菌16S rRNA V3～V4可变区进行测序,分析了土壤微生物的α多样性、物种丰度差异和组成情况,探讨了不同形态Sb和As在tc1(水耕熟化层)、tc2(渗育层)、tc3(犁底层)和tc4(水耕淀积层)的地球化学行为及其对细菌群落结构的影响.结果表明,研究区Sb和As的来源不同,Sb主要来源于大气沉降和人工投放,As则来源于成土母岩.变形菌门(Proteobacteria)和绿弯菌门(Chloroflexi)为各土层的主要优势菌门,具体表现为变形菌门(Proteobacteria)是tc1和tc2的优势菌门,绿弯菌门(Chloroflexi)是tc3和tc4的优势菌门.土壤剖面各土层多样性指数均在tc1达到最大值,在tc3达到最小值且差异不显著.相对重要性分析表明,总As、As(V)、TS和Fe(II)为影响多样性指数的主要因子.LEfSe分析表明,各土层差异指示种在不同分类水平上各不相同且tc1的数量高于tc2、tc3和tc4.如在门水平,tc1的差异指示种为疣微菌门(Verrucomicrobia),tc3为热袍菌门(Thermotogae),tc4为硝化螺旋菌门(Nitrospirae);在纲水平,tc1为α-变形菌纲(α-proteobacteria),tc2为β-变形菌纲(β-proteobacteria),tc3为热袍菌纲(Thermotogae),tc4为硝化螺旋菌纲(Nitrospirae).RDA分析和相对重要性分析表明,总As、As(III)、Sb(V)、总Sb和pH等对细菌门分类水平具有重要影响.共生网络分析进一步表明,Sb(III)和As(V)虽然对群落结构影响相对较小,但与特征性微生物却存在显著相关性,如Sb(III)与Defluviicoccus属显著相关,而As(V)对β-变形菌纲影响较为显著.更多还原

【Abstract】 In order to understand the adaptation mechanism of microorganisms to Sb and As pollution in the paddy soil, we took the paddy soil around the Banpo antimony mine and the antimony smelter in Dushan County, Guizhou Province as the research objects. Methods of field layout and indoor analysis, the V3～V4 variable region of bacterial 16 S rRNA gene was sequenced using Illumina high-throughput sequencing technology. We analyzed the soil alpha diversity, species abundance and composition, and studied the geochemical behaviors of different fractions of Sb and As in tc1(hydroponic maturing layer), tc2(seepage layer), tc3(plow layer),and tc4(hydroponic layer) of paddy soil profile. The results showed that the sources of Sb and As were different, Sb was mainly derived from atmospheric deposition and mining activity, while As was derived from the parent rock. Proteobacteria and Chloroflexi were the dominant phylums in the soil layer. Proteobacteria had higher relative abundance in both tc1 and tc2 layers, whereas Chloroflexi had higher relative abundance in tc3 and tc4 layers. The highest alpha diversity index of soil bacterial community in soil profile was found in the tc1, and whereas the lowest was observed in the tc3, although the difference was not significant. LEfSe analysis showed that the differences of indicator species were varied between layers at different classification levels and the number of tc1 was higher than that of tc2, tc3 and tc4.For example, the indicator species of tc1 was the Verrucomicrobia, tc3 was the Thermotogae, and the tc4 was the Nitrospirae at the phylum level; α-proteobacteria, β-proteobacteria, Thermotogae, Nitrospira were the indicator species in tc1, tc2, tc3, tc 4, respectively, at the class level. RDA and relative importance analysis showed that total As, As(III), Sb(V), total Sb, and pH played important roles in phylum classification. The co-occurrence network analysis further showed that although Sb(III) and AS(V) had relatively little effect on community structure, they had significant correlation with characteristic microorganisms. For example, Sb(III) was significantly related to Defluviicoccus, while As(V) had a significant effect on the proteobacteria.更多还原