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For further screening obvious role hydroxide bacteria on plant growth, the gradual development of microbial fertilizer to promote the sustainable development of agriculture. In this study, Shaanxi Province without hydrogen absorption enzyme legume nodulation of alfalfa (Medicago sativa) rhizosphere as research material, gradually improve the separation of hydroxide bacterial culture techniques;-depth understanding of the physiological and biochemical characteristics and identification enrich existing research hydroxide species of bacteria genus; explore the role of mechanisms to promote plant growth, the main content and the results are as follows: the use of continuing through H 2 gas circulating culture system to electrolysis of water produces H 2 , mixed with a pass into the air to form a flow rate of 280 mL / min, with H 2 amount of 4.16 × 10 -4 -2.42 × 10 -3 mol / L, a mixed gas, the hydroxide of the enriched soil bacteria, the enrichment of the soil samples by mineral salts solid culture medium, of the isolated and purified 37 bacteria. Gas chromatographic strains oxidation H 2 capacity, results show that the 8 strains of hydrogen absorption value greater than 2.44 × 10 -4 mol / L, accounting for the total number of measured strain 25.93%, initially identified as the hydroxide bacteria. Wherein the strain WMQ-7 and FMG-5 hydrogen absorbing value is greater than 12.28 × 10 -4 mol / L, while the strain WMQ-7 strongest ability of hydrogen peroxide, up to 19.90 × 10 -4 mol / L. Observed through 8 hydroxide form of the bacteria, and physiological and biochemical experiments, preliminary identification belonging Plesiomonas spp (Plesiomonas) fat the genus (Pimelobacte), the genus Pseudomonas (Pseudomonas), yellow genus (Xanthobacter ), Le Minuo spp (Leminorella), and the ground the genus (Terrabacter) and rare the spp (Rarobacter). Simultaneous detection of the optimal culture conditions of strain WMQ-7: optimum carbon source glucose, the optimum temperature of 30 ° C, the optimum pH 7.0. 8 hydroxide bacteria the wheat growth promoting experimental tablet test results showed that: the strain WMQ-7 FMG FMG-5 performance promoting wheat extremely significant, root length were increased compared with the blank control. 73.92%, 74.78%, 58.26%; shoot length than the blank control an increase of 34.64%, which strains FMG-3 processing wheat seedlings increased by 67.64%; wheat seed root part of the dry weight average value increased by 95.24% than the blank control. 57.14%, 47.62%. Strains FMG-5 WMQ-7, FMG-3 processing wheat in mature wheat grains, respectively, more than doubled compared with the control. Strain WMQ-7 FMG-5, FMG-3 post-harvest processing of wheat, weighty, milling, flour reducing sugar, total sugar content, protein content than the control improved to varying degrees, which strains FMG-3 processing wheat reducing sugar content was increased by 23.76%, total sugar content increased by 7.38% compared with the control. Strains FMG-5 the most significant impact on wheat protein content, protein content was increased by 22.86%. Two aspects of exploration from the ACC deaminase and siderophore hydroxide bacterial promote wheat growth mechanism. The use of thin-layer chromatography screening an ACC deaminase-positive strains WMQ-7, the the ninhydrin colorimetric detection of the strain of ACC deaminase activity of 0.671 U / μg. MSA-CAS and MKB-CAS, detection tablet screened positive strains produced siderophores through the medium color change. Strain WMQ-7 the MSA-CAS detection plate, blue medium around the colonies turn pink, while the in MKB-CAS detection plate, blue medium around the colonies turn yellow, indicating that the strain could be secreted siderophore. Using UV spectrophotometer iron carrier, the results show that the strains WMQ-7 secretion siderophore obvious absorption peaks at 404 nm absorbance value 0.834. Standard 2,3-DHBA wavelength scan control strain WMQ-7 secretion of siderophore type is not a catechol-type. Phenanthroline assay indirectly calculate the amount of strain WMQ-7 secrete siderophores produced for 7.1996μg/mL. FMG-3, FMG-5 16S rDNA sequence analysis and phylogenetic tree was constructed, the results show that there are large differences in kinship hydroxide bacterial strains WMQ-7, the genetic distance. 16S rDNA sequence length, strain WMQ-7 to 1451 bp, GC content of 53.8%, 99% homology Pseudomonas putida, to combine cell morphology and physiological and biochemical characteristics, further identification of strains WMQ-7 Pseudomonas putida (Pseudomonasputida) (GenBank Accession No. EU807744). Strains FMG-FMG-5 length 16S rDNA sequences were 1034 bp, 1394 bp; GC content of 51.7%, 54.45%. Strains FMG-5 and Rhizobium similarity at 94 percent, while the 16S rDNA sequences of strains FMG-3 is not found in the GenBank sequence than on the phylogenetic tree as a branch, speculated that strains FMG-3 alone is likely to is a new species.
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