不同演替阶段人工柠条林丛枝菌根真菌分子多样性研究

 采用PCR-DGGE和DNA克隆测序技术对黄土沟壑区一时间演替序列（5、13、20 a和42 a）上的人工柠条林的丛枝菌根真菌(Arbuscular Mycorrhizal Fungi;AMF)进行群落结构及多样性研究。结果显示,所有DNA序列聚为四个均属于AMF Glomus属的序列群,分别与Genbank上已登录的G.intraradices（同源性≥98%）、G. fasciculatum（=99%）、Glo18（=98%）和G. sp.（=98%）相关,这表明,在特定的时间点上柠条根系的AMF多样性十分低下。这四个序列群在5~20 a的柠条林中均出现,而在42 a的柠条林中只有G. sp.未出现,这表明,AMF群落组成并未随着柠条林的演替而发生显著改变,即AMF群落并未随着人工柠条林的恢复演替而得到恢复;土壤理化性质的稳定以及人工柠条林中的AMF群落与植被之间的正向反馈关系可能是导致这种现象的主要原因。

Molecular Diversity of Arbuscular Mycorrhizal Fungi in a Chronosequence of Caragana korshinskii Plantation

We used PCR-DGGE, DNA cloning and sequencing techniques to study the community structure and diversity of arbuscular mycorrhizal fungi (AMF) in a chronosequence of Caragana korshinskii plantation in gully region of the Loess Plateau. Phylogenetic analysis of all DNA sequences revealed four sequence groups, of which all grouped in the genus of Glomus. The four sequence groups showed high similarity to Genbank sequences of G. intraradices, G. fasciculatum, Glo18 and G. sp. respectively. Our results indicated an extremely low diversity of AMF presented in the C. korshinskii roots in a sampling time point. All of the four sequence groups presented in 5, 13 and 20-year sites, but G. sp. were not distinctly detected in 42-year site. It suggested AMF community composition in a chronosequence of C. korshinskii plantations was stable, and implicated the restoration of AMF community was not successful with the succession of C. korshinskii plantations. The little edaphic variation and the positive feedback relationship between AMF and plant communities in C. korshinskii plantation maybe result in such a phenomenon.