State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; Zhejiang Provincial Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration, Zhejiang A&F University, Hangzhou 311300, China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; Zhejiang Provincial Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration, Zhejiang A&F University, Hangzhou 311300, China.
Sci Total Environ. 2021 Jun 1;771:144779. doi: 10.1016/j.scitotenv.2020.144779. Epub 2021 Jan 25.
Plant invasion can markedly alter soil fungal communities and nitrogen (N) availability; however, the linkage between the fungal decomposition capacity and N mineralization during plant invasion remains largely unknown. Here, we examined the relationship between net mineralization rates and relevant functional genes, as well as fungal species composition and function following Moso bamboo (Phyllostachys edulis) invasion of evergreen broadleaf forests, by studying broadleaf forests (non-invaded), mixed bamboo-broadleaf forests (moderately invaded) and bamboo forests (heavily invaded). Fungal species composition and functional genes involved in organic matter decomposition (laccase and cellobiohydrolase), N mineralization (alkaline peptidases) and nitrification (ammonia monooxygenase) were determined via high-throughput sequencing and real-time PCR. Both net ammonification and nitrification rates were generally increased with bamboo invasion into the broadleaf forest, where the net ammonification rate, on average, was 10.8 times higher than the nitrification rate across the three forest types. The fungal species composition and ecological guilds were altered with bamboo invasion, as demonstrated by the increased proportion of saprotrophs but decreased proportion of symbiotrophs in the bamboo forest. The increased net ammonification rate in bamboo forest was positively correlated with both fungal species composition and functional groups, and the fungal lcc gene (for lignin breakdown) abundance explained 67% of the variation of the net ammonification rate. In addition, the gene abundance of ammonia-oxidizing bacteria (AOB) explained 62% of the variation of net nitrification rate across the three forest types. The increased soil ammonification and nitrification rates following bamboo invasion of broadleaf forests suggest that the bamboo-invasion associated increase in soil N supply provided a positive feedback that facilitated bamboo invasion into broadleaf forests.
植物入侵会显著改变土壤真菌群落和氮（N）的有效性；然而，植物入侵过程中真菌分解能力与氮矿化之间的联系在很大程度上仍不清楚。在这里，我们通过研究常绿阔叶林（未入侵）、混合竹阔林（中度入侵）和竹林（重度入侵），研究了毛竹入侵后净矿化率与相关功能基因以及真菌物种组成和功能之间的关系。通过高通量测序和实时 PCR 测定了与有机质分解（漆酶和纤维二糖水解酶）、N 矿化（碱性肽酶）和硝化（氨单加氧酶）相关的真菌物种组成和功能基因。随着毛竹入侵阔叶林，净氨化和硝化速率普遍增加，其中净氨化速率在三种森林类型中的平均值比硝化速率高 10.8 倍。随着毛竹的入侵，真菌的物种组成和生态类群发生了变化，竹林中腐生菌的比例增加，共生菌的比例减少。竹林中净氨化率的增加与真菌物种组成和功能群呈正相关，真菌 lcc 基因（用于木质素分解）的丰度解释了净氨化率变化的 67%。此外，氨氧化细菌（AOB）的基因丰度解释了三种森林类型中净硝化率变化的 62%。毛竹入侵阔叶林后土壤氨化和硝化速率的增加表明，土壤 N 供应的增加为毛竹入侵阔叶林提供了积极的反馈，促进了毛竹的入侵。
