不同时期艾比湖湿地盐角草群落土壤固氮微生物的多样性分析

Diversity of soil nitrogen-fixing microorganisms in Salicornia europaea community of Ebinur Lake wetland during different periods

摘要:

[目的]研究新疆艾比湖湿地不同季节盐角草根际和非根际土壤固氮微生物的多样性和丰富度与环境因子的相关性，以期探究在荒漠化和盐渍化不断严重的艾比湖湿地中随着季节变化的固氮微生物群落对恢复生态功能起到的潜在作用，为后续的湿地保护和退化恢复工作提供理论支持和数据基础。[方法]应用Illumina HiSeq PE250测序技术，分析6个土壤样本固氮微生物的多样性，结合相关的理化因子并利用RDA分析法探究土壤理化性质和固氮微生物菌落结构及丰富度的相关性。[结果]艾比湖湿地盐角草植物根际土壤的固氮微生物多样性高于非根际土壤，7月的土壤固氮微生物多样性高于10月和4月的土壤。土杆菌属（Geobacter）、假单胞菌属（Pseudomonas）、固氮菌属（Azotobacter）和慢生根瘤菌属（Bradyrhizobium）等为盐角草根际和非根际土壤中的共同优势菌属。这些固氮微生物优势菌属隶属于变形菌门（Proteobacteria）和蓝藻门（Cyanobacteria），且相对丰富度占比为85%和10%，其余各菌门共占比较少，仅为5%。土壤中固氮微生物的优势菌群与碱解氮（AN）、全氮（TN）、速效钾（AK）和有效磷（TP）呈显著相关。[结论]随着时间的推移土壤样本中固氮微生物的多样性和群落结构也发了改变，同一时期植物根际与非根际土壤中固氮微生物的群落结构并不相同。土壤的环境因子与固氮细菌的群落结构和丰富度的相关性研究可以为艾比湖湿地的退化恢复提供数据基础和理论支持。

关键词:艾比湖湿地;固氮基因(nifH);固氮微生物多样性;环境因子

Abstract:

[Objective] The primary goal of this study was to explore the correlation between the diversity and abundance of nitrogen-fixing microbes and the physicochemical factors of rhizosphere and non-rhizosphere soil types during different seasons. We aimed to explore the potential role of nitrogen-fixing microbial communities in restoring ecological functions. This study may provide the theoretical foundation and preliminary data for future studies in this field. [Methods] Illumina HiSeq PE250 sequencing technique was used to analyze the diversity of nitrogen-fixing microorganisms in six different soil samples. RDA analysis was used to explore the correlation between the physicochemical factors and the structure and abundance of nitrogen-fixing microbial communities in these soil samples.[Results] The diversity of nitrogen-fixing bacteria in rhizosphere soil was higher than that in non-rhizosphere soil. Additionally, the diversity observed in July was higher than that in October and April. Bacteria belonging to the genera Geobacter, Pseudomonas, Azotobacter and Bradyrhizobium were predominant in Salicornia europaea rhizosphere and non-rhizosphere soils. The predominant phyla of nitrogen-fixing microorganisms were Proteobacteria and Cyanobacteria, whose relative abundance accounted for 85% and 10%, respectively, while the others accounted for less than 5%. The predominant nitrogen-fixing microflora in the soil was significantly correlated with alkali-hydrolyzed nitrogen (AN), total nitrogen (TN), available potassium (AK), and total phosphorus (TP). [Conclusion] The diversity and community structure of nitrogen-fixing microorganisms in soil samples varied in different seasons. The community structure of nitrogen-fixing microorganisms was different in rhizosphere and non-rhizosphere soil types during the same period. These experimental results may provide the theoretical foundation and preliminary data for the restoration of Ebinur Lake wetland.

Key words:Lake Ebinur wetland;nitrogen-fixing gene (nifH);diversity of nitrogen fixation microorganisms;physic-chemical factors