中文关键词黑土有机碳官能团核磁共振波谱土壤真菌网络分析 英文关键词arable mollisolsorganic carbon functional groupssolid-state ¹³C-NMR technologysoil funginetwork analysis

作者	单位	E-mail
尚秋彤	常州大学环境与安全工程学院, 常州 213164	sqtldn@qq.com
黄瑞林	中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008
倪浩为	中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008
隋跃宇	中国科学院东北地理与农业生态研究所, 黑土区农业生态重点实验室, 哈尔滨 150081
孙波	中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008
梁玉婷	中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008	ytliang@issas.ac.cn

中文摘要 真菌在土壤有机质积累、转化以及养分循环中发挥着重要功能.本文利用高通量ITS扩增子测序和固态¹³C核磁共振波谱技术，比较低有机质（2%~5%）和高有机质（7%~9%）条件下，土壤真菌各类群间的互作关系及其与有机碳官能团结构的联系.¹³C-NMR分析结果表明，O-Alkyl C占总有机碳的比例随着有机质含量的升高而增大（25.8%~35.9%）.有机质含量越高，A/A-O（Alkyl C/O-Alkyl C）越小，有机质分解程度越低.真菌群落中粪壳菌纲（Sordariomycetes，14.33%~28.17%）和被孢毛霉菌纲（Mortierellomycotina，7.32%~23.14%）为优势类群，其相对丰度均随着土壤有机质含量的升高而显著增加（P<0.05）.网络分析结果表明，相比高有机质土壤，低有机质土壤中真菌生态网络的节点数、连接数和平均聚类系数较小，真菌互作关系更简单，且真菌与有机碳官能团联系更紧密，尤其与LOC联系更紧密.随机森林模型显示LOC对低有机质土壤真菌互作关系的解释量最高（10%），其次是难分解碳组分（ROC）.相比LOC对高有机质土壤真菌互作关系的贡献相对较小（7.4%）.在全球土壤碳损失日益严重的背景下，碳资源的限制，特别是LOC的减少，可能会降低土壤真菌群落的稳定性和多功能性. 英文摘要 Fungi play an important role in the accumulation and transformation of soil organic matter (SOM) and nutrient cycling. To investigate the relationship between the fungal community and soil organic carbon functional groups under gradient SOM contents in arable mollisols, arable mollisols with 2%-9% SOM content were collected in Northeast China. Solid-state ¹³C-NMR technology was used to explore the differences in the functional group structure of SOM, and ITS high-throughput sequencing was used to investigate the fungal community structure. The potential interactions between different taxonomic groups of soil fungal community and their associations with organic carbon molecular structures were compared by constructing molecular ecological networks under low SOM (2%-5%) and high SOM (7%-9%) conditions. The ¹³C-NMR results indicated an increase in the relative abundance of Alkyl C (25.8% to 35.9%). The decrease in Alkyl C/O-Alkyl C indicated a smaller degree of decomposition in high SOM soils. Sordariomycetes and Mortierellomycotina dominated the fungal community and their relative abundance increased with the SOM gradient (P<0.05) from 14.33% to 28.17% and from 7.32% to 23.14%, respectively. The network analysis showed simpler ecological topological properties of the fungal community in low SOM soils, with lower numbers of nodes, edges, and average clustering coefficients than those in high SOM soils. A closer relationship between fungi and organic carbon functional groups, especially LOC, was observed in low SOM soils. The random forest model showed that LOC had the largest amount for fungal interactions in low SOM soils (10%), followed by recalcitrant organic carbon (ROC). In comparison, LOC contributed less to the variations in fungal interactions in high SOM soils (7.4%). With globally increasing soil carbon loss, the limition of the carbon resources, especially the reduction of LOC, may reduce the stability and ecological functions of soil fungal communities.

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