摘要:城市硬化地表可减少土壤有机物输入，并改变土壤理化性质，由此可能影响土壤微生物群落结构和功能，但目前国内外相关研究较少。为研究不同树种下土壤微生物群落对硬化地表的响应，设置透水硬化地表（Pervious pavement，P）、不透水硬化地表（Impervious pavement，IP）和自然地表（Control，C）3个处理水平的地表类型，并栽种北方常见的常绿针叶树油松（pine，Pinus tabulaeformis）和落叶阔叶树白蜡（ash，Fraxinus chinensis）。采用氯仿熏蒸浸提法、磷脂脂肪酸法（PLFA）及BIOLOG培养法分别测定了土壤微生物量、群落结构和功能多样性。结果表明：（1）与自然地表（C）相比，硬化地表下土壤微生物生物量碳、氮含量显著降低（P < 0.05），土壤微生物群落组成和群落功能多样性发生了改变。透水和不透水硬化地表下土壤微生物细菌、真菌数量降低，真菌/细菌（fungi/bacteria，F/B）、cy/pre（环丙基脂肪酸/前体结构cyclopropyl fatty acid/monoenoic precursors）和sat/mono（一般饱和脂肪酸/单不饱和脂肪酸normal saturated fatty acid/monounsaturated fatty acid）等环境压力指标均显著升高（P < 0.05），且土壤微生物cy/pre值在不透水硬化地表下显著高于透水硬化地表下，表明不透水硬化地表下土壤环境压力更大；不透水硬化地表下土壤微生物对糖类、氨基酸类、羧酸类、胺类和聚合物的利用显著降低（P < 0.05），微生物群落功能丰富度及多样性指数显著降低（P < 0.05）。（2）土壤微生物群落结构和功能多样性在不同树种间存在一定差异。油松树下土壤微生物真菌、丛枝菌根真菌（arbuscular mycorrhizal fungi，AMF）和F/B值在透水和不透水硬化地表下均显著降低（P < 0.05），而白蜡树下只在透水硬化地表下显著降低（P < 0.05）；硬化地表使土壤微生物对糖类、氨基酸类和聚合物的利用强度在油松和白蜡树下表现出显著差异。硬化地表对土壤微生物的影响将进一步影响城市绿地的养分循环、树木生境和生态系统服务功能。



Abstract:Land pavement is popular during urbanization. It provides convenience to the daily life of citizens and urban development. However, it can inhibit urban plant growth by altering soil nutrients and microbial communities. Plants can purify the air as pollutants movers and alleviate the heat island effect by offering shade. Thus, it is vital to provide favorable growth conditions for plants. Consequently, it is very important to determine how land pavement affects soil microbial community structure and function as related to plant growth. In the current study, pervious (P) and impervious (IP) pavement were studied in reference to the natural surface (control, C) to determine the response of soil microorganisms under different types of pavement with pine (Pinus tabulaeformis) and ash (Fraxinus chinensis). Topsoil (0-20 cm depth) was analyzed by the well-developed methods of Biolog Ecoplate (BIOLOG) and phospholipid fatty acid (PLFA) profiles for microbial functional and structural diversity. Microbial biomass carbon (C_mic) and nitrogen (N_mic) were also examined. The results showed the following. (1) Compared to C, P and IP treatments decreased soil C_mic and N_mic and significantly changed soil microbial carbon source utilization patterns and soil microbial community structure by increasing F/B (fungi/bacteria), cy/pre (cyclopropyl fatty acid/monoenoic precursors), and sat/mono(normal saturated fatty acid/monounsaturated fatty acid). It is interesting that unlike fungi/bacteria and sat/mono, cy/pre under the IP treatment was significantly higher than that from the P treatment, with more stress in the former than the later. Moreover, IP treatment reduced soil microbial utilization of carbohydrates, amino acids, carboxylic acids, amines, and polymers. IP treatment also significantly decreased microbial community richness and diversity index by 27% and 10% for pine, and 70% and 37% for ash, respectively. (2) The effects of land pavement on soil microbial community structure and functional diversity differed with tree species. For pine, soil microbial fungi, arbuscular mycorrhizal fungi (AMF) and F/B were significantly reduced under P (40%) and IP (39%), whereas for ash they were significantly decreased by 38% only under P. Additionally, there were differences in the effects of land pavement on carbohydrates, amino acids, and polymers of soil microorganisms between pine and ash species. Pavement effects on soil microorganisms adversely affect nutrient cycling, tree habitat, and ecosystem service of urban green space at a large scale, and the present study provides some advice to the decision-makers during urban greening and development.





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