胡杨是中国西北干旱区绿洲重要的乔木树种,研究胡杨根际土壤真菌群落特征及其主要土壤影响因子,对胡杨林的保护和以胡杨为建群种的生态系统的恢复具有重要意义.该研究在额济纳胡杨林自然保护区设置3个样点,每个样地按照S形随机布点选25~30株胡杨取根际土,采用Biolog-FF微平板方法对89份土壤样本进行了真菌群落代谢特征及其影响因子分析.结果表明:(1)通过聚类将95种碳源划分为3个类群,其中53.8%的氨基酸类碳源分布在类群Ⅰ(OD值为0.106 1~0.316 4),83.3%的胺类碳源和70%的其他类碳源分布在类群Ⅱ(OD值为0.016 6~0.224 2),47.1%的羧酸类碳源分布在类群Ⅲ(OD值为0.232 1~1.115 5).(2)通过冗余分析,发现所有土壤因子对真菌群落代谢特征总的解释率为30.02%,而RDA1轴占该解释率的84.6%,电导率和速效钾与RDA1轴显著正相关且解释率最高.(3)沿着电导率降低的方向,样本在RDA2轴上的分布逐渐分散,表明随着电导率的降低,土壤肥力和质地条件对真菌群落代谢活性的影响增强.研究发现,胡杨根际土壤真菌群落的主要碳源利用类型为羧酸类、氨基酸类和部分碳水类,而对胺类和其他类碳源的利用程度较弱;土壤可溶性盐,特别是可溶性钾盐是影响真菌群落代谢特征的主要土壤因子,而土壤肥力和土壤质地因子只有在盐分含量较低的情况下才具有明显作用.%Soil fungi community play a significant role in many key ecosystem processes,such as litter decomposition and nutrient cycling.The biodiversity and activities of soil fungi are also very important for evaluating the ecosystem health.It is significant to study metabolic characteristics of fungi community and underlying environmental correlates in rhizosphere soils of Populus euphratica for the protection of arid ecosystem,considering the important status of the species in that harsh environment areas.In our study,we collected 89 soil samples from typical P.euphratica forest to explore the metabolic characteristics of fungi community and underlying environmental factors.The results showed that (1) Carbon sources used by fungi could be grouped into 3 clusters based on OD value.About 53.8% of amino acids could be included into clusterⅠ(OD:0.106 1-0.316 4),83.3% amines and 70% miscellaneous into cluster Ⅱ(OD:0.016 6-0.224 2),47.1% of carboxylic acids into cluster Ⅲ(OD:0.232 1-1.115 5).(2) Redundancy analysis (RDA) indicated that the total variances explained by soil factors was 30.02%,and RDA1 which was markedly correlated with electric conductivity and available potassium could explain 84.6% of its variances.(3) Samples at RDA2 axis were gradually dispersed with the decrease of salt,which may suggest soil fertility and soil texture may be the secondary important factor in determining the metabolic characteristics of fungi community.In conclusion,the dominant carbon sources used by fungi community in P.euphratica rhizosphere were amino acids,carboxylic acids,and some of carbohydrates,while weaker utilization intensities of amines and miscellaneous.Soil soluble salt,especially for the available potassium,was the most significant soil factor influencing the metabolic characteristics of fungi community.Soil fertility and soil texture were the secondary factors,only significantly correlated with metabolic characteristics of soil fungi community when the soil soluble salt content was low
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