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不同林龄红松根际土壤细菌群落结构和多样性分析

Analysis of the structure and diversity of rhizosphere soil bacterial communities in Pinus koraiensis of different forest ages

  • 摘要: 为探究林龄增长对红松人工林根际土壤微生物群落结构组成差异及功能特征,以10、32、42、52、62 a的红松人工林为研究对象,测定根际土壤理化性质,采用高通量测序技术对其根际土壤中细菌群落特征及功能进行分析。结果表明: 6—8月份不同林龄红松土壤细菌共获得细菌61门138纲290目390科921属711种;32a林龄红松人工林土壤有机质、全氮、碱解氮、速效钾和有效磷质量分数显著高于其它林龄,全钾质量分数在各林龄间无显著差异,全磷质量分数随林龄的增加从1.54 g/kg逐渐降低至0.81 g/kg;α多样性(Shannon指数)随林龄增长呈“先降低后升高”的趋势,在32a林龄林分中达到最低(9.84~9.91),而在62a成熟林中恢复至最高(10.27~10.44);在门水平上,细菌群落以变形菌门(19.54%~34.09%)、酸杆菌门(14.75%~20.70%)、疣微菌门(9.96%~21.53%)为主;属水平Ca. Udaeobacter在32 a富集最显著(最高18.97%);细菌功能涉及6类KEGG一级通路(代谢、环境信息处理等)及34类二级功能。氨基酸代谢(10.52~10.70%)和碳水化合物代谢(9.93~10.29%)为优势功能通路,32 a时达峰值;土壤细菌多样性主要受速效钾、pH及碱解氮含量的影响;而细菌群落结构则主要由全磷、全钾与碱解氮这三类因子所驱动。

     

    Abstract: To investigate how increasing forest age affects the structural composition and functional characteristics of rhizosphere microbial communities in Pinus koraiensis plantations, we studied 10-, 32-, 42-, 52-, and 62-year-old Pinus koraiensis plantations. We measured the physicochemical properties of rhizosphere soil and analyzed bacterial community features and functions using high-throughput sequencing technology. Results indicated: 1) From June to August, bacterial communities from Pinus koraiensis at different stand ages yielded 61 phyla, 138 classes, 290 orders, 390 families, 921 genera, and 711 species.2) Soil organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available potassium, and available phosphorus concentrations in 32-year-old Pinus koraiensis plantations were significantly higher than in other age classes. Total potassium concentrations showed no significant differences among age classes, while total phosphorus concentrations gradually decreased with increasing age, from 1.54 g·kg1 to 0.81 g·kg1.3) α diversity (Shannon index) exhibited a trend of “initial decline followed by increase” with increasing forest age, reaching its lowest point in 32-year-old stands (9.84–9.91) and recovering to its highest level in 62-year-old mature forests (10.27–10.44). 4) At the phylum level, bacterial communities were dominated by the phyla Proteobacteria (19.54%–34.09%), Acidobacteria (14.75%–20.70%), and Verrucomicrobia (9.96%–21.53%).At the genus level, Ca. Udaeobacter was most significantly enriched in 32-year-old stands (up to 18.97%). 5) Bacterial functions encompassed 6 KEGG level-1 pathways (metabolism, environmental signaling, etc.) and 34 level-2 functions. Amino acid metabolism (10.52%–10.70%) and carbohydrate metabolism (9.93%–10.29%) were dominant functional pathways , peaking at 32-year-old. 6) Soil available potassium, pH, and alkaline-hydrolyzable nitrogen were primary factors influencing soil bacterial diversity. Total phosphorus, alkaline-hydrolyzable nitrogen, and total potassium were key factors affecting soil bacterial community structure.

     

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