Journal of Pure and Applied MicrobiologyVol. 7 No. 4

Study of Microbial Distribution in the Arid Desert Terrain, Beishan Mountains Area, Gansu

Mei Liu1, Xiaoming Chen1,2*, E Zhang1, Chao Wang1, Chen Ruan1, Yan Xu1, Xiaoling Liu1 and Xuegang Luo1,2

1School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan - 621 010, China. 2School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang, Sichuan - 621 010, China.

Received on 23 September 2013 and accepted on 06 November 2013

 

ABSTRACT

In order to explore the microbial flora characteristics of rhizosphere soils in Gansu Beishan mountains area, rhizosphere soils alongside of typical plants were selected respectively from dense and sparse vegetation zones as materials. The quantity and distribution of three groups of microorganism were investigated by dilution method of plate counting. Additionally, 16S rDNA sequence analysis was used to identify the dominant bacteria. The results showed that microorganism quantity of arid soils in Beishan was similar to normal environment. Microbial number of non-rhizosphere soil in dense vegetation zone (49.2?105?CFU/g) was more than that in sparse vegetation zone (35.5?105?CFU/g). The total population of microorganism were bacteria> actinomycetes> fungi. Furthermore, both volume and range of microorganism were decreased with the increasing soil depth in the same area. The microbial number of dense vegetation zone exhibited that Salsola?abrotanoides>Asterothamnus?centrali-asiaticus> Nitraria sphaerocarpa> Ephedra?przewalskii, while the microbial number of sparse vegetation zone exhibited that Salsola?abuscula>Sympegma?regelii. The change in the number might be related to the plant root exudates. In detail, Salsola?abrotanoides and Asterothamnus?centrali-asiaticus could promote the growth of fungi and improve the soil alkaline condition. Whereas, the root exudates of Salsola?abuscula and Sympegma?regelii respectively existed mainly at the depth of 20~50 cm and 10~20 cm, could inhibit the growth of soil microorganism. By the analysis of 16S rDNA sequences, eight dominant strains were respectively identified as Kocuria?Polaris, Bacillus?niacin, Arthrobacter?crystallopoietes, Paenibacillus?tarimensis, Nocardiopsis?lucentensis, Arthrobacter?agilis, Bacillus?idriensis, and Promicromonospora?kroppenstedtii.

Keywords : Beishan mountains, Desert plants, Microbial flora, 16S?rDNA sequence analysis.