Responses of arbuscular mycorrhizal fungi to nitrogen addition: A meta-analysis
Responses of arbuscular mycorrhizal fungi to nitrogen addition: A meta-analysis
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DOI：
10.1111/gcb.15369
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发表时间：
2020-10-13
影响因子：
11.6
通讯作者：
Zhu, Biao
中科院分区：
文献类型：
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作者：
Han, Yunfeng;Feng, Jiguang;Zhu, Biao
丛枝菌根真菌在陆地生态系统碳、氮、磷循环中具有重要作用。增加氮沉降对AM真菌的影响必然会影响生态系统过程。然而，氮沉积如何影响AM真菌的可推广模式仍然知之甚少。在这里，我们进行了一个全球规模的荟萃分析，从94个出版物和101个网站，调查AM真菌的反应，氮添加，包括丰富的内部自由基（宿主根）和外部自由基部分（土壤），丰富度和多样性。并采用基于性状的功能团分析方法探讨了氮素对AM真菌生长的影响机制。结果表明，施氮显著降低了AM真菌的总丰度（-8.0%）。但根内和根外菌丝体数量的反应不一致：根定殖率显著下降（-11.6%），而根外菌丝体长度密度变化不显著。不同AM真菌功能团对氮素的响应不同，N处理使AM真菌功能团的丰度（孢子密度）和相对丰度均显著下降（分别为-29.8%和-12.0%），而土壤真菌功能团的丰度和相对丰度对N处理的响应不显著。这种不一致的反应，嗜根和嗜土壤的功能团主要是由土壤pH值的变化和根生物量的反应，分别调节。施氮对AM真菌丰富度和多样性的影响不显著，而AM真菌丰富度和多样性与土壤P的相对有效性（即土壤有效N/P比值）密切相关。总的来说，这项荟萃分析强调，考虑到基于性状的AM真菌公会，土壤磷的可用性和宿主植物C的分配可以大大提高我们对AM真菌群落在增加氮沉降下的细微动态的理解。
Arbuscular mycorrhizal (AM) fungi play important roles in carbon (C), nitrogen (N) and phosphorus (P) cycling of terrestrial ecosystems. The impact of increasing N deposition on AM fungi will inevitably affect ecosystem processes. However, generalizable patterns of how N deposition affects AM fungi remains poorly understood. Here we conducted a global-scale meta-analysis from 94 publications and 101 sites to investigate the responses of AM fungi to N addition, including abundance in both intra-radical (host roots) and extra-radical portion (soil), richness and diversity. We also explored the mechanisms of N addition affecting AM fungi by the trait-based guilds method. Results showed that N addition significantly decreased AM fungal overall abundance (-8.0%). However, the response of abundance in intra-radical portion was not consistent with that in extra-radical portion: root colonization decreased (-11.6%) significantly, whereas extra-radical hyphae length density did not change significantly. Different AM fungal guilds showed different responses to N addition: both the abundance (spore density) and relative abundance of the rhizophilic guild decreased significantly under N addition (-29.8% and -12.0%, respectively), while the abundance and relative abundance of the edaphophilic guild had insignificant response to N addition. Such inconsistent responses of rhizophilic and edaphophilic guilds were mainly moderated by the change of soil pH and the response of root biomass, respectively. Moreover, N addition had an insignificant negative effect on AM fungal richness and diversity, which was strongly related with the relative availability of soil P (i.e. soil available N/P ratio). Collectively, this meta-analysis highlights that considering trait-based AM fungal guilds, soil P availability and host plant C allocation can greatly improve our understanding of the nuanced dynamics of AM fungal communities under increasing N deposition.