关键词: 氮沉降, 毛竹, 丛枝菌根真菌, 根际土壤, α多样性

Abstract: Moso bamboo (Phyllostachys edulis) has high economic value and is mainly distributed in the areas with severe nitrogen (N) deposition in China. Arbuscular mycorrhizal fungi (AMF) are an important link between roots and rhizosphere soil of Moso bamboo. However, their responses to N deposition are unclear. We conducted an experiment with four treatments, including low nitrogen (N30), medium nitrogen (N60), high nitrogen (N90) and control (N0), to examine the effects of N deposition on community composition and diversity of AMF in the rhizosphere soil of Moso bamboo. Specific primer pairs (AMV4.5NF and AMDGR) were used for amplicon sequencing of the fungal 18S rRNA genes. The results showed that the concentrations of total phosphorus, total nitrogen, alkalihydrolyzable nitrogen, and organic matter in soils of the N60 treatment were significantly higher than those of other treatments. Soil available phosphorus concentration was significantly higher in the N30 treatment compared with the control. Soil moisture and soil pH significantly decreased with increasing N deposition. N deposition shifted the composition of AMF community in the rhizosphere soil of Moso bamboo. At the genus level, the AMF was dominated by Glomus (96.20%-99.70%). At the species level, with the increases of N deposition rates, the relative abundance of virtual species (Virtual taxa, VT)sp. VTX00219 was significantly increased from 4.32% to 38.00%, 36.64% and 33.93%, respectively; the relative abundance of sp. VTX0089 significantly decreased from 41.78% to 1.56%, 2.39% and 0, respectively; the relative abundance of sp. VTX00370 significantly reduced from 12.86% to 0.39%, 1.31% and 1.25%, respectively. Alkalihydrolyzed nitrogen concentration, pH, and soil moisture were the main factors affecting the composition and diversity of AMF community in the rhizosphere soil of Moso bamboo. In addition, N deposition altered αdiversity of AMF community in the rhizosphere soil of Moso bamboo, with a significant increase in N60 treatment and a decline in N90 treatment. The key driving factors affecting α-diversity of AMF community shifted from soil alkali-hydrolyzed N concentration and available N∶P ratio to soil pH with increasing N deposition. Our results are helpful to better understanding the effects of N deposition on AMF community in the rhizosphere soil of Moso bamboo, and provide scientific reference for exploring sustainable management of Moso bamboo forests.

Key words: nitrogen deposition, Moso bamboo, arbuscular mycorrhizal fungi, rhizosphere soil, α diversity