龙门山地震带土壤细菌多样性的研究

Soil Bacterial Diversity in Longmen Mountain Seismic Zone

采用16S r DNA变性梯度凝胶电泳(Denaturing Gradient Gel Electrophoresis,DGGE)技术,结合不同土壤样品的理化性质差异,分析龙门山地震带土壤细菌多样性。结果表明,不同的土壤样品其理化性质存在着明显的差异,三种植被类型的土壤(杂木林、竹林和松树林)中,杂木林的土壤pH值和全氮含量最高,竹林最低;而土壤碱解氮、速效磷、速效钾和有机质含量则是杂木林比竹林高,松树林最低。对DGGE优势条带测序分析表明,回收的11个优势条带(条带A^K)中,条带A、C、D、F、G和H属于变形菌门,条带E、J和K属于酸杆菌门,条带B属于放线菌门,条带I属于装甲菌门,变形菌门占细菌总类群的54.55%,说明龙门山地震带土壤优势菌群为变形菌门细菌。细菌群落多样性与土壤理化性质相关性的统计分析结果显示,影响细菌群落多样性的主要环境因子在杂木林土壤中为速效钾(r=0.80,P>0.05),竹林为有机质(r=0.97,P>0.05),松树林则是pH值(r=0.35,P>0.05),说明龙门山地震带不同植被类型土壤中的细菌群落对土壤理化性质的需求不同。由于地震能够破坏土壤结构,改变土壤理化性质,从而导致土壤细菌群落多样性发生改变,因此,研究龙门山地震带土壤细菌多样性为震后灾区重建工作和维持龙门山地震带生态系统的可持续性提供了科学依据。

The bacterial diversity in Longmen mountain seismic belt was analyzed by using 16S rDNA Denaturing Gradient Gel Eleetrophoresis （DGGE） technique and soil physical and chemical properties were measured. The results showed that there were significant differences in soil physical and chemical properties among different soil samples. Among three vegetation types （Miscellaneous forest, Bamboo forest and Pine forest）, the value of soil pH and the content of soil total nitrogen were the highest in miscellaneous forest but the lowest in Bamboo forest. The contents of soil available nitrogen, available phosphorus, available potassium and organic matter were higher in miscellaneous forest than that in Bamboo forest, while they were the lowest in Pine forest. Sequencing analysis results for DGGE of 11 dominant bands （band A ~ K） showed that bands A, C, D, F, G and H belonged to Proteobacteria, bands E, J and K belonged to Acidobacteria, band B belonged to Actinobacteria and Strip I pertained to Armatimonadetes. About 54.55% of total bacteria belonged to Proteobacteria, which indicates that the soil dominant bacteria in Longmen mountain seismic zone was Proteobacteria. The pearson correlation （r） between bacterial community diversity and physicochemical properties showed that the main environmental factors affecting the diversity of bacterial community were available potassium, organic matter and pH, respectively, in the miscellaneous forest （r = 0.80, P 〉 0.05）, the bamboo forest （r = 0.97, P 〉 0.05） and the pine forest （r = 0.35, P 〉 0.05）, which indicated that the bacterial communities in different vegetation types in Longmen mountain seismic zone had different requirements for soil physical and chemical properties. The earthquakes destroyed soil structure and changed soil physical and chemical properties, which would lead to the change of soil bacterial community diversity. The study of soil bacterial diversity in Longmen mountain seismic belt has provided a scientific basis for the reconstruction of the disaster area and the ecosystem - sustainable development in Longmen mountain seismic zone.