Effectsof Phosphate Solubilizing Bacteria On Soil Microorganisms And Their Temporal And Spatial Distribution Characteristics

The colonization and distribution mechanism of plant growth promoting bacteria in soil is not clear.The study was aimed to screen efficient organophosphate-degradation bacteria from environment, then study their growth promoting mechanism and temporal and spatial distribution.We screened 35 strains of organophosphate-degradation bacteria from bulk soil of grass by organophosphate-degradation medium, and studied the promoting growth characteristics by biochemical assays, then 5 representative strains were selected to carry out the cucumber pot experiment. The results showed that strain G3-6 had the strongest ability to solubilize organic phosphorus, the ratio of hydrolysis circle diameter(HD) and colony diameter (CD) was 3.28.Strain G3-6 had the highest ability to promote cucumber growth than other strains. Compared with CK, G3-6 can increase the fresh weight and dry weight and the height of cucumber seedlings by 71.53%, 69.78%and33.55%, respectively. Compared with the positive control Bacillussubtilis F-H-1, G3-6 can increasethe fresh weight and dry weight and the height of cucumber seedlings by 2.52%,21.14% and 8.27%. respectively.The results of correlation analysis showed that the ability of organophosphate-degradation maight play a more important role in promoting cucumber growth than otherfunctions. Strain G3-6 was identified as Pseudomonas sp. by 16S rRNA analysis.We studied on the microbial diversity of different treatmentsof cucumber pot experiment by high throughput sequencing. PcoA analysis showed that different treatments had significant effects on soil microbial community composition; Lefse analysis was used to analyze the differences among different treatments and found that there were significant differences in microbial species among different treatments; CCA analysis showed that active phosphate had significant effect on soil microbial community. The cucumber root box experiment was carried out using a high efficient organophosphate-degradation bacterium G3-6 and Gluconacetobacter liquefaciens qzr14 which was screened in the early study and has high efficientability of inorganic phosphorus-solubilizing.The results showed that G3-6 and qzrl4 of the soil bulk density and soil water content analysis results are consistent in time scale, spatial vertical scale and spatial horizontal scale; The plant characteristics analysisresults showed that qzr14 had obvious promoting effect on cucumber seedlings.We choiced high efficient inorganic phosphorus-solubilizing bacterium qzr14 to carry out the real-time PCR. The results showed that the numbers of Gluconacetobacter liquefaciens was significantly higher in qzrl4 treatment soil than in CK soil on the time scale, and there was a decreasing trend; 15-30 days after inoculation, there was no significant difference in the numbers of Gluconacetobacter liquefaciens in different treatments and different soil layers; The number of Gluconacetobacter liquefaciens in the upper soil was higher than that in the subsoilin spatial vertical scale; There was no Gluconacetobacter liquefaciens in the inner layer and the outer layer of soil in the spatial horizontal scale.