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应用生态学报 ›› 2022, Vol. 33 ›› Issue (6): 1622-1628.doi: 10.13287/j.1001-9332.202206.032

• 研究论文 • 上一篇    下一篇

亚热带米槠天然林土壤氨氧化微生物对模拟氮沉降的响应

冯蒙蒙1,2, 林永新1,2*, 贺子洋1,2, 刘小飞2,3, 陈仕东2,3, 宛颂1,2, 段春健1,2, 叶桂萍4, 贺纪正1,2   

  1. 1湿润亚热带山地生态国家重点实验室培育基地, 福州 350007;
    2福建师范大学地理科学学院, 福州 350007;
    3福建三明森林生态系统与全球变化国家野外科学观测研究站, 福建三明 365000;
    4闽江学院海洋研究院, 福州 350108
  • 收稿日期:2021-06-18 接受日期:2022-02-10 发布日期:2022-12-15
  • 通讯作者: *E-mail: yxlin@fjnu.edu.cn
  • 作者简介:冯蒙蒙, 女, 1996年生, 硕士研究生。主要从事土壤微生物生态学研究。E-mail: 1923005353@qq.com
  • 基金资助:
    国家自然科学基金项目(41930756, 42077041)和福建省自然科学基金项目(2020J01187)资助。

Responses of soil ammonia-oxidizing microorganisms to simulated nitrogen deposition in a natural Castanopsis carlesii forest

FENG Meng-meng1,2, LIN Yong-xin1,2*, HE Zi-yang1,2, LIU Xiao-fei2,3, CHEN Shi-dong2,3, WAN Song1,2, DUAN Chun-jian1,2, YE Gui-ping4, HE Ji-zheng1,2   

  1. 1Cultivation Base of State Key Laboratory for Subtropical Mountain Ecology, Fuzhou 350007, China;
    2School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China;
    3Fujian Sanming Forest Ecosystem and Global Change National Observation and Research Station, Sanming 365000, Fujian, China;
    4Institute of Oceanography, Minjiang University, Fuzhou 350108, China
  • Received:2021-06-18 Accepted:2022-02-10 Published:2022-12-15

摘要: 我国亚热带地区是全球氮沉降的热点区域。氮沉降会影响氨氧化微生物的丰度和群落结构,进而改变土壤微生物驱动的养分循环。目前对新近发现的完全氨氧化菌认识不足,极大地制约了对森林土壤氨氧化微生物响应氮沉降的整体认识。本研究以福建省三明市辛口镇格氏栲自然保护区长期模拟氮沉降处理土壤为研究对象,利用实时定量PCR方法,研究氨氧化微生物(包括氨氧化细菌AOB、氨氧化古菌AOA和完全氨氧化菌comammox Nitrospira),尤其是完全氨氧化菌的amoA基因丰度。模拟氮沉降处理包括:不添加N(CK)、低氮(添加40 kg N·hm-2·a-1,LN)和高氮(添加80 kg N·hm-2·a-1,HN)。结果表明: 8年的氮添加降低了土壤pH值和有机碳含量,提高了土壤硝态氮含量。供试土壤的AOB丰度低于检测限,无法获得目的片段。高氮处理显著提高了AOA丰度,但对完全氨氧化菌clade A和clade B丰度无显著影响。两种氮添加处理均降低了完全氨氧化菌/AOA值,表明氮添加降低了完全氨氧化菌在亚热带森林土壤氨氧化微生物类群中的相对竞争力。针对完全氨氧化菌clade A和clade B的扩增都存在非特异性产物,表明针对森林土壤的高特异性和覆盖度设计引物的必要性。Clade A和clade B丰度与总氮和铵态氮含量呈显著正相关,clade B丰度还与有机碳含量呈显著正相关。总之,模拟氮沉降提高了AOA在亚热带米槠天然林土壤硝化过程中的相对重要性,这些发现可为该地区应对全球变化和氮沉降的风险评估提供理论依据。

关键词: 氮添加, 亚热带森林, 硝化微生物, 完全氨氧化菌

Abstract: Subtropical region of China is one of the global hotspots receiving nitrogen deposition. Nitrogen deposition could affect the abundance and community structure of ammonia oxidizers including ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and complete ammonia oxidizer (comammox Nitrospira), with consequences on soil nutrient cycling that are driven by microorganisms. There is limited understanding for the newly discovered comammox Nitrospira in the subtropical forest soils. Here, we investigated the effect of simulated N deposition on abundances of soil ammonia oxidizers in the Castanopsis fargesii Nature Reserve in Xinkou Town, Sanming City, Fujian Province, China. Soil samples were collected from the field plots which received long-term nitrogen deposition with different dosages, including: CK, no additional treatment; LN, low nitrogen deposition treatment, dosage of 40 kg N·hm-2·a-1; and HN, high nitrogen deposition treatment, dosage of 80 kg N·hm-2·a-1. After 8-year treatment, simulated N deposition decreased soil pH and organic matter content, and increased nitrate content. We failed to amplify the amoA gene of AOB in the tested soils. High nitrogen deposition increased the abundance of AOA, but did not affect the abundance of comammox Nitrospira clade A and clade B. The ratio of comammox Nitrospira to AOA decreased with N addition, indicating that N addition weakened the role of comammox Nitrospira in nitrification in the subtropical forest soils. However, there were strong non-specific amplifications for both comammox Nitrospira clades A and B, highlighting the demand for the development of high coverage and specificity primers for comammox Nitrospira investigations in the future. The abundance of comammox Nitrospira clade A was positively correlated with total nitrogen (TN) and NH4+ concentration, while that of clade B was positively associated with soil organic carbon (SOC), TN and NH4+ Concentration. Overall, our findings demonstrated that simulated N deposition increased the relative importance of AOA in nitrification in the natural Castanopsis carlesii forest soil. These findings could provide theoretical support in coping with global change and N deposition in these regions.

Key words: nitrogen addition, subtropical forest, nitrifiers, comammox Nitrospira