毛乌素沙地典型克隆植物根际AM真菌多样性研究

为阐明毛乌素沙地3种典型克隆植物沙鞭Psammochloa villosa(Trin.)Bor.]、羊柴(Hedysarum leaveMaxim)和油蒿(Artemisia ordosica Krasch.)根际AM真菌多样性,2006年的5月、7月、10月从毛乌素沙地选取东北缘的中国科学院植物研究所鄂尔多斯沙地草地生态研究站和西南缘的陕西榆林珍稀沙生植物保护基地两个样地,按0~10 cm、10~20 cm、20~30 cm、30~40 cm、40~50 cm 5个土层采集3种克隆植物根际土壤样品,研究了其根际AM真菌物种多样性和生态分布。在分离出的4属23种AM真菌中,球囊霉属(Glomus)15种,无梗囊霉属(Acaulospora)5种,巨孢囊霉属(Gigaspora)2种,盾巨孢囊霉属(Scutellospora)1种。摩西球囊霉(G.mosseae)是沙鞭根际的优势种,黑球囊霉(G.melanosporum)是3种克隆植物共同的常见种;不同属种的AM真菌生态分布亦存在差异。AM真菌孢子密度、种的丰度和物种多样性指数均表现为在研究站样地的羊柴根际最高。该研究结果表明,毛乌素沙地的3种典型克隆植物与AM真菌之间形成良好的共生关系,这对开发漠境AM真菌资源和利用菌根生物技术维护沙地生态系统结构的完整性具有重要意义。

Diversity of arbuscular mycorrhizal fungi associated with clonal plants in Mu Us Sandy Land

Arbuscular mycorrhizal (AM) fungi is important in maintaining the functions and biodiversity of arid-land ecosystems and is also an indispensable factor in the restoration and reestablishment of vegetation. In particular, AM fungi are ubiquitous symbiotic fungi and plants. Clonal plants possess wider ecological neighborhoods than non-clonal plants. Clonal plants constitute a form of resource for the restoration of the Mu Us Sandy Land. Clonal plants have been identified as the driver of change in community environments and greatly contribute to the maintenance of community functions in the restoration process of vegetation. Clonal plants considerably enhance the ability of self-rehabilitation of sandy landscapes. To elucidate species diversity and ecological distribution of AM fungi associated with 3 kinds of clonal plants (Psammochloa villosa, Hedysarum leave, Artemisia ordosica) in Mu Us Sandy Land, two representative sites (Research Station and Yulin) were selected from the northeast and southwest of Mu Us Sandy Land. Soil samples at 50 cm depth of rhizosphere of clonal plants were collected in 4 replicates at each location and divided into sections corresponding to 0~10 cm, 10~20 cm, 20~30 cm, 30~40 cm, 40~50 cm depths in May, July and October 2006. A total of 23 AM fungal species belonging to 4 genera were isolated and identified. Of these, 15 species belonged to Glomus, 5 to Acaulospora, 2 to Gigaspora, and 1 to Scutellospora. G. mosseae was the dominant species in the P. villosa rhizosphere; G. melanosporum was the common species in the rhizosphere of 3 kinds of clonal plants. The ecological distributions were different among species and AM fungi genera. AM fungi spore density, species richness and species diversity index were highest in H. leave rhizosphere in the Research Station. The results showed that AM fungal species diversity was rich in clonal plant rhizospheres in Mu Us Sandy Land. Also the spatial distribution dynamics of AM fungal species in Mu Us Sandy Land was significant. This paper described the diversity and distribution of AM fungi in the rhizospheres of three kinds of clonal plants, which provided the basis for reestablishing ecosystems and sustaining economic development in Mu Us Sandy Land.