青海不同林分土壤微生物群落结构(PLFA)

  目的  明确三江源高寒湿地微生物群落结构特征以及植被和土壤理化特性对三江源高寒湿地微生物群落特征的影响。  方法  以三江源地区典型高寒湿地为研究对象，采用磷脂脂肪酸（Phospholipid fatty acid, PLFA）法，探究土壤微生物群落结构特征及其调控因子。  结果  三江源地区高寒湿地的总PLFA为84.76 ± 38.03 nmol g⁻¹，其中革兰氏阳性菌、革兰氏阴性菌、真菌、放线菌、丛枝菌根真菌和其他PLFA分别为14.98 ± 6.21、17.77 ± 8.17、2.60 ± 1.60、4.22 ± 2.38、1.84 ± 1.22和43.41 ± 21.06 nmol g⁻¹。土壤微生物群落结构受到植被生物量和土壤理化特性的共同影响，而气候因素对其影响相对较弱。放线菌与土壤全氮、土壤湿度、硝态氮和地下生物量呈正相关关系；总PLFA、细菌还与总氮和铵态氮呈正相关关系，与土壤容重呈负相关关系；革兰氏阳性菌与总氮、土壤湿度、铵态氮、硝态氮、地下生物量和土壤有机碳呈正相关关系；革兰氏阴性菌与土壤湿度、铵态氮、硝态氮和地下生物量呈正相关关系；而丛枝菌根真菌和真菌受到生物量与土壤理化特性的影响相对较小。  结论  植物和土壤理化特性的共同作用是调控三江源高寒湿地微生物群落结构的重要因素，这有利于更深入地理解陆地生态系统生物地球化学循环。

et al. Consequences of biodiversity loss for litter decomposition across biomes

  Objective  Although soil microbial communities have significant effects on ecosystem construction and function, the researches on them were few conducted in the Three Rivers Source Regions alpine wetlands. Therefore, it is necessary to explore the soil microbial communities and their controlling factors.   Method  In this paper, using the method of phospholipid fatty acid (PLFA), the soil microbial community characteristics and their controlling factors were studied.   Result  Results showed that total PLFA was 84.76 ± 38.03 nmol g⁻¹, gram-positive bacteria, gram-negative bacteria, fungi, actinomycete, arbuscular mycorrhizal fungi and other PLFAs were 14.98 ± 6.21, 17.77 ± 8.17, 2.60 ± 1.60, 4.22 ± 2.38, 1.84 ± 1.22 and 43.41 ± 21.06 nmol g⁻¹, respectively. Soil microbial communities were controlled by plant biomass, soil physical and chemical properties, and effects from climate factors were minor. Actinomycete has a positive relationship with soil total nitrogen, soil moisture, NO₃⁻−N, and belowground biomass. Total PLFA and bacteria have a positive relationship with soil total nitrogen, soil humidity, NO₃⁻−N, NH₄ ⁺ −N, negative relationship with bulk density. Gram-positive bacteria have positive relationships with soil total nitrogen, soil moisture, NO₃⁻−N, NH₄ ⁺ −N and belowground biomass. Gram-negative bacteria have positive relationships with soil moisture, NO₃⁻−N, NH₄ ⁺ −N, and belowground biomass. Arbuscular mycorrhizal fungi and fungi have a weak relationship with biomass and soil physical and chemical properties.   Conclusion  Plant, soil physical and chemical properties jointly affect soil microbial community structure in Three Rivers Source Regions alpine wetlands, which contribute to deeply understanding biogeochemical cycle in terrestrial ecosystems.