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酸沉降显著影响着土壤生态系统的结构组成与系统功能,但对我国南方花岗岩发育的酸性土壤细菌群落结构及多样性的影响还知之甚少。因此,本文以酸沉降影响严重的亚热带地区花岗岩发育的剖面(0~100 cm)土壤为对象,采用不同酸度的HCl-NH_4Cl溶液(pH=3.5,4.5,5.5)对A层(0~12 cm)、B层(12~50 cm)与C层(50~100 cm)土壤分别进行分批次淋溶实验(Batch方法),探讨在此特定实验条件下酸溶液作用前后土壤细菌群落结构及多样性的变异特征。研究结果表明,利用Miseq技术对土壤细菌16S r RNA基因进行高通量测序与分析发现酸溶液可以显著降低A层、B层和C层土壤的细菌多样性,pH3.5酸处理土壤的细菌多样性降低幅度最大,pH4.5酸处理土壤的降低幅度最小。HCl-NH_4Cl酸溶液可显著影响花岗岩土壤细菌的群落结构,并导致土壤细菌的优势种群发生变化,其中,A层土壤细菌优势种群由酸杆菌门(Acidobacteria)转变为变形菌门(Proteobacteria),B层和C层土壤细菌优势种群由变形菌门(Proteobacteria)转变为放线菌门(Actinobacteria)。细菌相对丰度变化特征和主成分分析结果表明,pH3.5、pH4.5和pH5.5三种酸处理之间没有明显差异,但不同层次土壤细菌群落结构对同一pH酸溶液的响应不一致,这是由A、B、C层土壤理化性质的差异性,从而对酸处理的响应不同所致。因此,HCl-NH_4Cl酸溶液对土壤细菌群落结构、优势种群和多样性产生的显著影响与土壤的性质密切相关,并反作用于土壤发生、演变及生态系统演替。
Acid deposition significantly affects the structural composition and system function of soil ecosystem, but little is known about the influence of the bacterial community structure and diversity of acid soils in southern granite developed in China. Therefore, in this study, the soil profiles from 0 to 100 cm in the A layer (0 ~ 100 cm) with different acidity HCl-NH_4Cl solution (pH = 3.5, 4.5 and 5.5) (B) (12 ~ 50 cm) and C (50 ~ 100 cm) soils were investigated by batch method. The effects of acid solution on the bacterial community structure and diversity Sexual variation characteristics. The results showed that the use of Miseq technology for high-throughput bacterial 16S rRNA gene sequencing and analysis found that acid solution can significantly reduce the A, B and C soil bacterial diversity, pH3.5 acid soil bacteria The largest decrease was observed in pH, and the lowest decrease was observed in soil with pH4.5 acid treatment. HCl-NH_4Cl acid solution can significantly affect the community structure of bacteria in the granitic soil and lead to the change of the dominant population of soil bacteria. Among them, the dominant bacterial population of soil layer A was changed from Acidobacteria to Proteobacteria, The predominant population of soil bacteria in layers C and C was changed from Proteobacteria to Actinobacteria. The characteristics of relative abundance of bacteria and principal component analysis showed that there was no significant difference between the three acid treatments of pH3.5, pH4.5 and pH5.5. However, the response of bacterial community structure to different pH acid solutions was inconsistent, This is caused by the differences in the physico-chemical properties of the soils A, B, and C, resulting in different responses to the acid treatment. Therefore, the significant influence of HCl-NH4Cl acid solution on soil bacterial community structure, dominant population and diversity is closely related to the nature of the soil, and it is opposite to the occurrence and evolution of soil and ecosystem succession.