Preliminary Study On Soil Bacteria In The Northern Alp Regions Of Hengduan Mountains

43 soil samples of 35 plots,located by GPS(Global Position System),were collected from the regions of northern alp of Hengduan Mountains of Qinghai-Xizang Plateau.Quantities of bacteria were determined with the dilution plate technique.The soil bacteria were identified and the correlations between the quantities of bacteria and some factors which including area,agrotype,land-use type, altitude and soil depth were analyzed by using the software of DPS.According to the quantities, communities and their distribution,the bacteria diversity was also studied.Potential which could antagonize to pathogen,solubilize phosphate and potassic-compound was also analyzed.The result showed that the average quantity of bacteria was about 1.03×10⁷±8.57×10⁶ cfu·g^-1 dry soil in the regions of northern alp of Hengduan Mountains.In the same depth and different regions,the quantity of bacteria in the highest sample is 100 times as many as it in the lowest sample.Bacteria quantities from high to low were as follows:in different regions,Songlinkou (2.05×10⁷±1.80×10⁷ cfu·g^-1 dry soil)＞Que'er Mountain(1.01×10⁷±3.38×10⁷ cfu·g^-1 dry soil)＞Zheduo Mountain(7.03×10⁶±5.23×10⁶ cfu·g^-1 dry soil).In different soil textures,clay Ioam(1.79×10⁷±3.11×10⁷ cfu·g^-1 dry soil)＞heavy clayey soil(1.32×10⁷±1.01×10⁷ cfu·g^-1 dry soil)＞powder sandy loam (8.8×10⁶±8.80×10⁶ cfu·g^-1 dry soil)＞sand loam(7.34×10⁶±6.62×10⁶ cfu·g^-1 dry soil)＞loam soil(4.23×10⁶±4.23×10⁶ cfu·g^-1 dry soil);In different land utilization way,forest land(1.65×10⁷±.56×10⁷ cfu·g^-1 dry soil)＞grass land(4.56×10⁶±4.00×10⁶ cfu·g^-1 dry soil)＞brush forest land(4.22×10⁶±3.66×10⁶ cfu·g^-1 dry soil).At the same plot,there were more bacteria in upper(0～20cm) than in deepersoil layers(20～40cm).Bacteria quantity was changed with altitude,but the degree of the impact is not great.A total of 668 bacteria isolates were collected from the soil in the northern alp regions of Hengduan Mountains.15 bacteria genera were identified.Among these genera,Cellulomonas spp.,Pimelobacter spp., Micrococcus spp.,Bacillus spp.,Agromonas spp.and Gluconobacter spp.,were isolated more frequently at 54.29%,60.00%,51.43%,100.00%,54.29%and 28.57%.In addition,B.cereus and B.spaericus was also bacillus of main population,and its isolation frequency were 80.0%and 51.43%,respectively.In different regions,the genera of main population were Bacillus spp.and Pimelobacter spp.,In loam soil and sand loam,the genera of main population were Pimelobacter spp..In powder sandy loam,powder sandy loam and clay loam,the genera of main population were Bacillus spp..In different land utilization way,the quantity of bacillus is highest than other bacteria genera.The abundance(S),Shannon-wiener's diversity(H′),Pielou's evenness(E) and dominance index(D) were 7.3714±4.7035,1.0144±0.4575,0.3746±0.1689å’Œ0.4955±0.2249,respectively.In different location,the abundance(S),Shannon-wiener's diversity(H′),Pielou's evenness(E) and dominance index(D) were different.Even if,in the same abundance(S)n,The Shannon-wiener's diversity(H′), Pielou's evenness(E) and dominance index(D) were different.Among 203 isolates,there were 25 isolates had obvious antagonistic effects against Rhizoctonia solani and 37 isolates had obvious antagonistic effects against Fusarium graminearum.In addition, there were 10 isolates against the two plant pathogens,and the percent inhibition of 6 isolates metabolites were more than 50%.There were 18 isolates which mainly belong to Bacillus spp.and Pimelobacter spp.were abiophosphate-solubilizing bacteria,and 17 isolates which mainly belong to Arthrobacter spp.solubilized organic-phosphate.