| Hydrogen-oxidizing bacteria are Plant Growth-Promoting Rhizobacteria,the boosting of the hydrogen-oxidizing bacteria may have a remarkable effect on the rhizospheric soil microbial populations, reduce or restrain the disoperation of some pathogenic microorganism. Some hydrogen-oxidizing bacterias can release 1-a minocyclop ropane-1-carboxylate (ACC) deaminase, which can degrade ACC, as the biosynthesis precursor of the ethane. Thus it can promote the growth of the plant. Certain hydrogen-oxidizing bacterias can synthsis some compounds or the secondary metabolin, all of which can paly a role in the growth of the paint, by the means of reducing the usage amount of the chemical fertilizer, suppressing the growth of the pathogenic bacterias, protecting the edatope and ameliorating the rhizospheric microecology. All of these can be utilized by the plants or help the plants absorb the nutriment from the entironment. In this paper, we screened the hydrogen-oxidizing bacteria, with the greatest hydrogen absorption, from the rhizosphere of the Legume palnts Alfalfa, Soybean, Locust etc. Here in we screened the strain of secreting siderophore and the strain ACC deaminase. The cultural condition of the strain and the property of siderophore were also analysed.The results are as follows:The capacity of H2-oxidizing was tested by Gas Chromatography (GC). It demonstrated that, the hydrogen absorption value of the strain WMQ-7, FMG-3 and FMG-5 were all more than 8.74×10-4 mol/L. The strain WMQ-7 possessed the greatest capacity, up to 19.90×10-4mol/L. This three hydrogen-oxidizing bacterias belong to Pseudomonas and Pseudomonas selectively.The growth-promoting test of the three hydrogen-oxidizing bacterias were implement on the wheats, the result showed as follows, the strain FMG-5, WMQ-7, FMG-3 and the mixed bacterias can promote the growth distinctly. The length of roots respectively increased by 28.6%,34.3%,34.4% and 20.1% compared with the control. The length of sprouts increased by 31.9%,32.1%,31.7%,24.6%. The fresh weights and the dry weights were 50.1%,41.4%, 29.3%,24.1% and 58.2%,50.1%,41.6%,33.3%. The plant lengths increased 14.5%,20.1%, 11.7%,18.3% averagely. The numbers of the wheat kernel were more than 30% compared with the control, promoting the increment of the wheat obviously. The ear of the wheat elongated 28.6%,33.3%,17.9%,13.1%. The content of the reducing sugar, the total sugar and the protein in the flour were all improved more or less. The content of the reducing sugar was 35.5%,64.5%,45.2%,38.7%, the total sugar was 14.2%,28.6%,17.1%,20.1% and the protein was 16.9%,24.6%,20.2%,18.5% in comparison with the controls.WMQ-7, a positive strain of ACC deaminase, was screened by TLC. The activity of WMQ-7 was 0.671U/μg, tested by ninhydrin colorimetry. Besides, the cultural condition of the WMQ-7 producing ACC deaminase and the zymologic properties were also affirmed.The positive strain of Siderophore was screened by the modified CAS method. The results showed, the strain WMQ-7 can secrete the Siderophore. On the plate of CAS, the blue culture medium around the bacterial colony turned into yellow. By the o-phenanthroline detection method, it can be reckoned that the content of the Siderophore in the WMQ-7 was up to 6.8512μg/mL. The analysis of the physicochemical property displayed that the Siderophore in the WMQ-7 was not catechol, but the hydroxamate-type siderophore. This Siderophore did not include the peptide bond, but may contain non-peptide bond amino acids or have other forms of amino structure, not a peptide siderophore. |
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