中文摘要：

为探索梭梭根际土壤微生物结构特征及其与肉苁蓉寄生的关系,应用磷脂脂肪酸（PLFA）法分析了5—8月份梭梭生长季节的根际土壤微生物种类及群落结构特征,采用湿筛倾注-蔗糖离心法对其根际土壤AM真菌进行了初步分离和鉴定,并分析了肉苁蓉寄生与梭梭根际微生物及环境因子间的相关性。结果表明,5—7月3个月份的梭梭根际土壤微生物磷脂脂肪酸种类及含量均显著高于8月份,总磷脂脂肪酸和AM真菌磷脂脂肪酸以6月份含量最高。梭梭根际土壤共鉴定出AM真菌4属35种,它们分别为球囊霉属（Glomus）22种、无梗囊霉属（Acaulospora）7种、多孢囊霉属（Diversispora）3种和巨孢囊霉属（Gigaspora）3种。其中以黑球囊霉（Glomus melanosporum）和双网无梗囊霉（Acaulospora bireticulata）为优势种群,并且发现了与寄生有关的巨孢囊霉属AM真菌。6月份和8月份的AM真菌孢子数量最多,而5月份的AM真菌孢子数量最低。6月份梭梭根际土壤提取液得到的肉苁蓉种子萌发率（65.94%）和田间接种寄生率（59.19%）均为最高值,而5月份土壤提取液测试得到的肉苁蓉种子萌发率最低。因此,推测梭梭根际AM真菌可能参与了肉苁蓉的寄生过程。相关分析表明梭梭根际土壤微生物种类和数量主要与土壤温湿度和土壤理化性质相关性较大,其中可能与寄生有关的真菌数量与土壤温度呈显著正相关;肉苁蓉寄生率与土壤温度及土壤养分呈显著负相关。研究为解析梭梭根际土壤微生物在肉苁蓉寄生过程中的作用以及指导肉苁蓉人工种植提供参考。

英文摘要：

The aim of this study was to analyze the effects of the microbial community structure in the rhizosphere soil of Haloxylon ammodendron on parasitism by Cistanche deserticola. The microbial community structure and arbuscular mycorrhizae （AM） fungal species were determined in samples collected from May 2013 to August 2013 fumigation-extraction, phospholipid fatty acid （PLFA） analysis, and wet sieving and centrifugation methods. by chloroform These findings were then used to reveal tile relationships between parasitism by C. deserticola, the microbial community of H. ammodendron and environmental factors. The results showed that species diversity and the overall quantity of microbial cells were significantly more abundant than in August, and that the PLFA content and total number of AM fungi were higher in samples collected in June. The PLFA concentration data were subjected to principal component analysis （PCA）, and the first two principal components （PC1, PC2） accounted for 90.12% and 9.21% of the total variation, respectively. This confirmed that the soil microbial community of H. ammodendron changed significantly during growth between May and August. Specifically identified PLFAs, including fatty acids that represented bacteria and fungi, were distributed on the right side of the load diagram, while fatty acids that represented actinomycetes were distributed on the left side of the load diagram. Thus, these results indicate that during H. ammodendron growth, total PLFA, PLFA representing bacteria and fungi, and PLFA representing actinomycetes all decreased from May to August. Thirty-five species of AM fungi from four genera were identified using the wet-sieving and centrifugation method. These included 22 species of Glomus, seven species of Acaulospora, three species of Diversispora, and three species of Gigaspora. The dominant species were Glomus melanosporum and Acaulospora bireticulata. The number of AM fungal spores, calculated using the counting method, was highest in June and lowest in May.