攀枝花不同海拔高度烤烟农田红壤中氨氧化细菌与氨氧化古菌的群落结构分析

为探究攀枝花干热河谷区农田土壤氨氧化古菌（Ammonia oxidizing archaea，AOA）与氨氧化细菌（Ammonia oxidizing bacteria，AOB）群落对海拔高度的响应特征，深入认识该区域的氮素循环过程。以攀枝花米易县不同海拔（1600 m、1800 m和2000 m）农田红壤为研究对象，运用化学分析和末端限制性片段长度多态性（Terminal restriction fragment length polymorphism，T-RFLP）分别测定土壤理化性质、AOA和AOB群落组成及多样性，研究不同海拔农田土壤中AOA和AOB群落变异及其驱动因子。研究结果显示，不同海拔农田土壤pH均小于7，土壤有机碳（SOC）、全氮（TN）、速效钾（AK）和铵态氮（NH₄⁺-N）含量随海拔升高而降低，碱解氮（AN）、有效磷（AP）和硝态氮（NO₃^--N）含量随海拔升高先增加后降低；随海拔升高，AOA群落多样性指数增加，而AOB群落多样性指数先增加后降低；AOA以亚硝基球菌属（Nitrososphaera）为优势菌群，AOB以亚硝化螺菌属（Nitrosospira）为优势菌群；土壤有机碳（SOC）、速效钾（AK）和硝态氮（NO₃^--N）是影响该区域农田土壤AOA和AOB群落发育的主要因子。总体而言，攀枝花干热河谷区不同海拔农田土壤AOA和AOB群落结构变化明显，土壤硝态氮、速效钾和有机碳是影响AOA和AOB群落结构变异的主要因子；研究结果可为揭示干热河谷区农田红壤氮循环相关微生物的海拔分布格局提供理论依据。

Community structure analysis of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in red soil of flue-cured tobacco farmland at different altitudes in Panzhihua city, China

This papers aims to explore the response of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) communities to elevation changes in the dry-hot valleys of Panzhihua City, China, and further reveal the nitrogen biogeochemical cycling of this area. Soil samples were collected from the tobacco cultivation field of different altitudes (e.g. 1600 m, 1800 m, and 2000 m) in the dry-hot valleys of Miyi county, Panzhihua City, China. Chemical analysis and terminal restriction fragment length polymorphism (T-RFLP) were used to analyze the soil physicochemical properties and community structures and diversity of AOB and AOA, respectively. The variation of AOA and AOB communities and the driving factors in farmland soils at different altitudes were also investigated. The results showed that the pH value of soils from the three different elevations were below seven which suggests that the soils being studied were acidic soils. The contents of soil organic carbon (SOC), total nitrogen (TN), available potassium (AK) and ammonium nitrogen (NH₄⁺-N) decreased along the increase of elevation. The contents of alkali-hydrolyzable nitrogen (AN), available phosphorus (AP), and nitrate nitrogen (NO₃^--N) first increased and then decreased along the increase of elevation. The highest contents of the AN, AP, and NO₃^--N were detected in the 1800 m elevation while the lowest were detected in the 2000 m. The diversity index of AOA community increased along the increase of altitude while the diversity index of AOB peaked in 1800m, and both the lowest diversity index of AOA and AOB were detected in 1600 m elevation. Nitrososphaera and Nitrosospira were the dominant species of AOA and AOB in the dry-hot valleys of Panzhihua City. Redundancy analysis (RDA) showed that the SOC, AK, and NO₃^--N were key factors in shaping the AOA and AOB communities. In total, both of the composition and diversity of soil AOA and AOB community varied significantly along the increase of altitude in the dry-hot valleys in Panzhihua City, and closely related with SOC, AK, and NO₃^--N. The results provide a theoretical basis for revealing the altitude distribution pattern of nitrogen cycling related microorganisms in red soil in dry- hot valley.