中文摘要：

2013年7月从内蒙古磴口,宁夏银川、沙坡头和甘肃民勤采集沙蒿（Artemisia desertorum）、红花锦鸡儿（Caragana rosea）、白刺（Nitraria tangutorum）、柠条锦鸡儿（Caragana korshinskii）等4种沙冬青（Ammopiptanthus mongolicus）伴生植物的根系样品,采用形态特征结合r DNA ITS序列分析进行真菌分类鉴定,研究了深色有隔内生真菌（DSE）群落组成和物种多样性。从4种伴生植物根样中共分离鉴定7类DSE（即Alternaria、Curvularia、Embellisia、Phialocephala、Phoma、Podospora和Pleosporales）,其中Alternaria、Embellisia、Curvularia和Podospora为荒漠生态系统首次报道的DSE。同一样地伴生植物与沙冬青DSE群落组成差异明显,不同样地沙冬青与伴生植物DSE物种多样性指数差异显著。结果表明,自然条件下沙冬青DSE定殖率和物种数量,特别是产孢种类和数量多于其伴生植物,暗示DSE能够与沙冬青根系形成更好的共生关系,增强沙冬青对极端荒漠环境的生态适应性。

英文摘要：

Aims Dark septate endophytes（DSE） extensively colonize in plant root tissues in different ecosystems.However,our understanding of the ecological significance of DSE in semiarid and arid lands is limited.The main objective of this study was to compare the community composition and species diversity of DSE in Ammopiptanthus mongolicus and its companion plants in desert habitats.Methods Healthy root samples of Ammopiptanthus mongolicus＇ s companion plants,Artemisia desertorum,Caragana rosea,Nitraria tangutorum and Caragana korshinskii,were collected separately from four main locations of Ammopiptanthus mongolicus plantation in Dengkou of Nei Mongol,Minqin of Gansu,Yinchuan and Shapotou of Ningxia in July 2013.Important findings A total of 103 strains belonging to seven species（i.e Alternaria,Curvularia,Embellisia,Phialocephala,Phoma,Podospora and Pleosporales） of DSE were isolated from the four types of companion plants by means of morphological identification and molecular identification.Among the seven genera,Alternaria,Embellisia,Curvularia and Podospora are found for the first time in desert ecosystems.Ammopiptanthus mongolicus and its companion plants at the same site had significantly different community composition of DSE.Ammopiptanthus mongolicus and its companion plants at different sites had significantly different DSE diversity index.The colonization and species richness of DSE,especially the species and the quantity of spores were higher in roots of Ammopiptanthus mongolicus than in its companion plants.This study supports the results that DSE can form a better symbiotic relationship with the roots of Ammopiptanthus mongolicus than with its companion plants,and can enhance the ecological adaptability of Ammopiptanthus mongolicus to the extreme desert environment.