中文摘要：

通过研究黄土高原典型林木根际土壤微生物群落结构,为正确评价该生态恢复区土壤环境恢复状况提供理论依据.利用湿筛倾析法、涂平板法和BIOLOG法研究了陕北黄土高原4种典型林木丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）孢子密度与土壤微生物群落结构多样性.结果表明,沙棘AMF孢子密度为刺槐的2.24倍,顺序为沙棘〉狼牙刺〉柠条〉刺槐,不同林木土壤细菌和放线菌数量达极显著差异（p〈0.01）,真菌数量差异不显著（p〉0.05）.同一林木土壤细菌对BIOLOG-ECO板中碳源的利用优势种类和利用程度呈现明显的差异性;主成分分析表明对主成分1和主成分2贡献大的碳源为14种和8种,柠条和沙棘土壤典型变量值的变异（离散）较小,而狼牙刺和刺槐土壤典型变量值的变异较大.相关性分析表明,AMF孢子密度与细菌数量、氨基酸类、多胺类和芳香化合物类碳源呈极显著正相关（p〈0.01）,与真菌数量、放线菌数量和细菌总代谢活性呈显著正相关（p〈0.05）,但是与羧酸类、糖类和多聚物类碳源相关性不显著（p〉0.05）.AMF孢子密度可以作为评价陕北黄土高原林木土壤细菌生理代谢类群及其多样性的环境生物学指标.

英文摘要：

Determination of the soil microbial community structure in rhizospbere of typical tree species in the Loess Plateau can be of great theoretical significance for correctly assessing the characteristics of soil ecological rehabilitation of the Loess Plateau. In this study, spore density analysis, microbial cultivation and BIOLOG were employed to evaluate the AMF spore density and soil microbial community diversity under four tree species with veslcular-arbuscular mycorrhizae in ecological rehabilitation area of the Loess Plateau, north Shaanxi Province. The results show that the different tree species differed significantly in both soil microbial number and microbial functional diversity, AMF spore density of Hippophae rhamnoides soil is 2.24 times than that of the Robinia pseudoacacia soil,and the rank as following order： Hippophae rhamnoides 〉 Sophora viciifolia 〉 Caragana microphyUa 〉 Robinla pseudoacacia . The statistical significant are detected in the bacteria and actinomyees numbers, however, there is no statistical significance in fungi number among the treatments. The principle component analyses indicates that scatter of Caragana microphylla and Hippophae rhamnoides are smaller than that of Sophora viciifolia and Robinia pseudoacacia, these results suggest that the soil community structure strongly varied among the different tree species. Numbers of carbon sources related to the first two components are 14 and 8. Correlation analysis shows that the AMF spore density appeared extremely significantly and positively correlated with the number of bacteria, and the metabolic of amino acids, amines and aromatic compounds, respectively. Moreover, AMF spore density positively correlated with the average well color development （AWCD）, nevertheless, no correlations are found among AMF spore density, carboxylic acids, carbohydrates and polymers.These results suggest that AMF spore density is shown to be an important environmental biology parameter used in correctly assessing the soil bacteria metabolic c