论文部分内容阅读
陆地生态系统中植物种对土壤微生物群落结构的影响不一,而喀斯特生态系统中植物种对土壤微生物群落结构影响的研究尚未见报道.本研究利用磷酸脂肪酸(PLFA)法,分析了黔中高原型喀斯特常绿落叶阔叶混交林5个优势树种—窄叶石栎(Lithocarpus confinis Huang)、圆果化香(Platycarya longipes Wu)、滇鼠刺(Itea yunnanensis Franch.)、安顺润楠(Machilus cavaleriei H.Lév.)、云贵鹅耳枥(Carpinus pubescens Burkill)—与土壤理化性质对土壤微生物群落组成和生物量的影响.在测试的212个土壤样品中共检测出132种PLFA,每个样品土壤微生物平均PLFA数量和生物量分别为65.97和11.22μgg-1.土壤表层(0-10 cm)的土壤微生物PLFA数量与下层(10-20 cm)土壤接近,但前者土壤微生物生物量显著高于后者(P＜0.05).树种影响土壤微生物PLFA数量,但对土壤微生物生物量没有影响.云贵鹅耳枥附近的土壤微生物PLFA数量显著高于其他树种(P＜0.05),而其他树种土壤微生物PLFA数量接近.土壤微生物生物量与表层土壤的理化性质无显著相关,但与下层土壤的有机碳、全氮和全磷含量呈显著正相关(P＜0.05).总之,黔中高原型喀斯特森林真菌/细菌生物量比率低,微生物总生物量低,但微生物群落多样性高.树种对土壤微生物群落多样性产生影响.“,”Aims The relationships between plant species and soil microorganisms remain indeterminable in different ecosystems worldwide.In karst ecosystems,soil microbial(SM)community structure and their environmental driving factors are poorly explored,and the relationships between plant species and soil microorganisms are unclear.This study aimed to characterize the general patterns of SM community composition and biomass,and to explore the specific tree species and soil physiochemical properties highly related to SM community diversity and biomass in a karst forest.Methods The effects of tree species on SM community composition and biomass were firstly investigated on the basis of 212 soil samples collected from five dominant tree species(Lithocarpus confinis Huang,Platycarya longipes Wu,Itea yunnanensis Franch.,Machilus cavaleriei H.Lév.and Carpinus pubescens Burkill)through phospholipid fatty acid(PLFA)analysis of a karst evergreen and deciduous broad-leaved mixed forest in central Guizhou Province,southwestern China.The relationships between SM community structure and tree species and soil physiochemical properties were statistically analysed.Important Findings A total of 132 SM-PLFA biomarkers were detected.The average number of SM-PLFA biomarkers and microbial biomass in each soil sample were 65.97 and 11.22 μg g-1,respectively.Tree species influenced the number of SM-PLFA biomarkers but not the SM biomass.The number of SM-PLFA biomarkers of C.pubescens was significantly higher than that of other species(P＜0.05);the numbers of SM-PLFA biomarkers amongst other species showed no significant difference.Microbial biomass showed no relationships with the soil physiochemical properties of nutrient-rich surface soils but positively correlated(P＜0.05)with soil organic carbon,nitrogen and phosphorus concentrations in deeper soils.The karst forest in the plateau-surface terrain of central Guizhou Province presented a low fungal-to-bacterial ratio,low microbial biomass storage and high microbial community diversity.Specific tree species affect the SM community diversity in this kind of karst forest.