【摘要】 【目的】研究黄土丘陵沟壑区不同人工林恢复对土壤微生物群落结构多样性产生的影响,为该区植被恢复评价提供数据参考。【方法】以山西吉县典型刺槐和油松人工林以及自然恢复的荒草地为研究对象,采用磷脂脂肪酸(PLFA)生物标记法(MIDI系统),分别对土壤表层0～20 cm和20～40 cm土层的PLFA种类进行分析,比较不同人工林植被恢复后土壤微生物PLFA数量以及微生物群落结构的差异,并探讨土壤化学性质对土壤微生物群落结构的影响。【结果】土壤微生物PLFA总量,细菌、放线菌、革兰氏阳性菌和丛枝菌根真菌PLFA含量及多样性指标(Shannon-Wiener、 Simpson及Pielou指数)均呈现出刺槐林最高、油松林次之,且均显著高于荒草地的趋势(P <0.05)。2种人工林土壤中表征环境胁迫的直链饱和脂肪酸/单不饱和脂肪酸(SAT/MONO)值显著低于荒草地(P <0.05)。主成分分析结果显示,不同植被类型及土层深度的土壤微生物群落结构存在差异,且3种植被表层土壤微生物群落结构之间的差异达到了显著水平(P <0.05)。冗余分析和Pearson相关分析结果显示,土壤微生物群落结构变化的主要影响因素是土壤全氮含量和pH值。【结论】刺槐和油松人工林的恢复对土壤微生物群落结构多样性有显著影响,对土壤生态系统的修复具有积极意义。与油松相比,刺槐更有利于土壤微生物状况的改善。更多还原

【Abstract】 [Objective] This paper aims to investigate the effects of artificial vegetation restoration on soil microbial community composition in the loess hilly-gully region, and provide data reference for regional vegetation restoration evaluation. [Method] Three typical vegetation types, including Robinia pseudoacacia, Pinus tabuliformis plantation and grassland, were chosen in Jixian County, Shanxi Province of northern China. Soil samples from depth of 0-20 cm and 20-40 cm were collected respectively, and soil microbial community composition was evaluated by phospholipid fatty acid(PLFA) analysis(MIDI-Sherlock system). Based on the PLFA analysis, we studied the differences between soil microbial PLFA contents and soil microbial community after restoration, and further explored the effect of soil chemical properties on soil microbial community structure. [Result] Results showed that total PLFAs, biomasses of bacteria, actinomycetes, gram-positive bacteria, arbuscular mycorrhizal fungi and diversity indicators(Shannon-Wiener, Simpson and Pielou index) followed the order of Robinia pseudoacacia > Pinus tabuliformis > grassland(P < 0.05). Meanwhile, the ratio of Saturated fatty acids to Monounsaturated fatty acids(SAT/MONO) in the two plantations was significantly lower than grassland(P < 0.05), which implied that environmental stress on soil microorganisms had reduced. Principal component analysis indicated that soil microbial community structure differed among various vegetation types and soil depths, and that the difference reached a significant level in topsoil(P < 0.05). Redundancy analysis and Pearson correlation analysis showed that soil total nitrogen and pH were the main factors leading to the changes of soil microbial community structure. [Conclusion] The restoration of Robinia pseudoacacia, Pinus tabuliformis impacted the diversity of soil microbial community structure significantly, and both typical plantations had positive effect on soil ecosystem restoration. Our findings suggest that Robinia pseudoacacia was more conducive to the improvement of soil microbial ecological environment than Pinus tabuliformis.更多还原