Response of decomposition dynamics of ectomycorrhizal fungal fruit bodies to N addition depends on decomposition stage in a coniferous forest

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Ectomycorrhizal (ECM) fungi profoundly regulate soil biogeochemical cycles and associated climate feedback through exudation and turnover. However, how ECM fungal fruit bodies decomposition dynamically responses to atmospheric nitrogen (N) deposition remains unclear. Here, we conducted a 20-week ECM fungal fruit bodies decomposition experiment to monitor the temporal dynamics of its mass and compositions loss under three different N addition levels in an ECM-dominated forest. We simultaneously determined soil microbial properties to identify the potential microbial processes for ECM fungal fruit bodies decomposition dynamics in response to different N addition levels. Our results showed that N addition promoted the mass loss of fungal fruit bodies in the early decomposition stage, which was characterized by the increased release of labile compositions. In contrast, N addition mitigated the mass loss of fungal fruit bodies in the later decomposition stage, accompanied by the more retention of labile and resistant compositions. Moreover, the early positive effect of N addition on fungal fruit bodies decomposition was attributed to the increase of microbial abundance and hydrolytic activity, while the later negative effect was related to the suppression of fungal abundance and peroxidase activity. These results highlight that the response of decomposition dynamics of ECM fungal fruit bodies to N addition was closely related to decomposition stage. Collectively, our study provides new insights into the ECM fungal turnover and its ecological feedback under atmospheric N deposition.