关键词: 生物防治, 根瘤内生菌, 烟草赤星病菌, 16S rDNA测序, 系统发育

Abstract: In order to understand the community diversity and its dynamic changes of soil fauna in different habitats of Fukang oasis, a field investigation was conducted in April, July, September, and mid November, 2010. Seven different habitats including timber forest, shelter forest, nursery, cropland, saline-alkaline land, shrub land, and desert grassland were chosen, and hand-sorting and modified Tullgren and Baermann methods were adopted to isolate the soil fauna in 0-20 cm layer, with the community structure, distribution characteristics, and seasonal dynamics of soil fauna analyzed. A total of 11098 individuals were collected, belonging to 35 groups, among which, Nematoda, Rotifera, and Collembola were the dominant groups. There existed significant differences in the individual number, group number, and community diversity of soil fauna among different habitats and seasons (P<0.05). In the seven habitats, the Shannon diversity index was in the order of timber forest > shelter forest > shrub land > cropland > salinealkaline land > nursery > desert grassland. The spatiotemporal distribution analysis of soil fauna in different habitats indicated that there was an obvious surface gathering, and the distribution had significant differences among seasons and soil layers (P<0.05). The individual number was the largest in autumn, followed by in spring and winter, and the least in summer. The Jaccard similarity index of the soil faunal communities in different habitats was 0.25-0.50, belonging to medium dissimilarity. The results of the betweengroups clustering and sorting showed that the seven habitats could be divided into four types, i.e., artificial forest habitat, anthropogenic disturbance habitat, shrub habitat, and desert habitat. These findings suggested that there existed obvious habitat and seasonal differences in the community composition and diversity of soil fauna in different habitats of Fukang oasis.

Key words: phylogenetic analysis, endophytic bacteria of root nodules, Alternaria longipes, 16S rDNA sequencing, biocontrol.