【摘要】 研究了新疆天山以北三工河流域自然生境下梭梭(Haloxylon ammodendron)、琵琶柴(Reaumuriasoongonica)、隐子草(Cleistogenes chinensis)3种植被群落的土壤微生物碳源利用差异,分析了土壤理化性质与微生物总体活性、功能多样性的相关关系.采用BIOLOG生态板检测了各微生物群落对31种单一碳源的利用情况,结果表明,3种群落的微生物总体活性(AWCD)(F=41.877,P<0.001)、功能多样性(Shannon指数)(F=164.680,P<0.001)、丰富度(R值)(F=20.818,P=0.02)差异显著,其中梭梭植被下微生物群落的AWCD值、Shannon多样性指数、R值明显高于其他两种植被的微生物群落.土壤pH(相关系数=0.958,P<0.001)、土壤总碳相对含量(相关系数=0.718,P<0.05)与微生物总体活性(AWCD)呈显著相关,对微生物碳源利用有重要影响,而土壤可溶盐总量、含水率则与AWCD相关性不显著,微生物群落碳源利用功能多样性和丰富度与土壤理化性质均无显著相关关系.对于所研究的31种单一碳源,梭梭植被下微生物群落的利用情况也好于其他两种植被类型,对11种单一碳源利用情况较好,而琵琶柴、隐子草植被微生物群落分别则仅能对其中6种和5种碳源有较好的利用能力.更多还原

【Abstract】 Soil microbial process plays an important role in the conversion of soil organic carbon into inorganic carbon,which is significant for the global carbon cycle.The aim of this study was to investigate the microbial functional diversity of carbon source utilization in three vegetation types under natural conditions along Sangong River basin in Fukang,Xinjiang,China.The three typical vegetation types were dominated by Haloxylon ammodendron,Reaumuria soongorica,and Cleistogenes chinensis,respectively.The soil type is saline soil in this area with varied alkalinity.BIOLOG method was used to determine capability of soil microorganisms in utilizing 31 types of single carbon source.Correlation between soil physicochemical property(pH,water content,total soluble salt) and AWCD(the average well color development),Shannon diversity index,richness value were analyzed.Microbial AWCD in H.ammodendron plot was significantly higher than that of the other two plots(P<0.01).pH value(pearson correlation=0.798,P<0.01) and total carbon content(pearson correlation=0.655,P<0.05) of the soil were closely associated with the value of AWCD,while the effect of water content and total soluble salt was not significant.In this study,the H.ammodendron vegetation had the highest soil total carbon content as well as the highest soil alkalinity while the ability of utilizing carbon source of its soil microbial community was higher than the other two vegetation types.The analysis of normalised optical density(OD) data with PCA(principal component analysis) showed that eleven carbon sources(five types of carbohydrates,two types of amino acid,four types of carboxylic acids) were well used by the soil microbes of H.ammodendron vegetation,six carbon sources(one of the carbohydrates,three of amino acid,two of carboxylic acids) were better metabolized in R.soongorica community.In addition,the soil microbes in C.chinensis vegetation only effectively utilized five out of thirty-one single carbon sources.It was assumed that higher total carbon content and alkalinity would result in higher utilization in the soil microbial community.This result will be benefit for the management of desertification and will contribute to the understanding of the underground carbon process in the saline soil in arid area and the research works on carbon cycle.更多还原