| Hydrogen oxidizing bacteria are used to colonize plant roots and stimulate plant growth as a kind of rhizosphere growth-promoting bacteria,which has potential application value.In this paper,using Trifolium repens L roots soil as research material,gas-cycle incubation system was used to enrich hydrogen oxidizing bacteria.And the strains were isolated and identified.The growth-promoting characteristics of hydrogen-oxidizing bacteria were preliminarily understood through the determination of phosphorus-solubilizing,ACC deaminase activity,secretion of IAA and iron carrier ability of the strain.The high quality strain S-1-4 with the potential of promoting growth was screened.The changes of wheat seeds soaked in bacteria solution after being treated with different concentrations of hydrogen were analyzed and compared.The changes of soil microbial population structure were analyzed and compared after being treated with H2.The experimental results are as follows:Nine strains with strong ability of hydrogen oxide were screened by MSA medium and gas chromatography.We can observe the morphology of strains,detect their physiology and biochemistry,and use 16S r DNA for bacterial species identification.So the final genus identification results showed that the 9 hydroxide bacteria were Mycobacterium,Arthrobacter,Sinorhizobium,Rhodococcus,Agromyces,Aminobacter and Pseudarthrobactersulfonivorans.The results of growth promoting characteristics showed that all strains could secrete IAA.Most of the bacteria had the ability of iron carrier,phosphorus solubilization and ACC deaminase,indicating that the growth-promoting effects of the selected oxidizing bacteria may involve multiple mechanisms of action.The results of wheat growth promotion experiment showed that the growth indexes of seeds soaked in different bacterial solutions were significantly better than those of the control.The root length and plant height of wheat seedlings increased in varying degrees,especially the concentration of hydrogen in 7.2mmol/L had a great effect on the growth-promoting ability of hydrogen-oxidizing bacteria,which provided a powerful experimental basis for further study of the growth-promoting effect of hydrogen-oxidizing bacteria.The results of bacterial community diversity experiment showed that the abundance of Proteobacteria and Actinobacteria changed significantly compared with the soil samples treated with air,and the change was more significant when the concentration of hydrogen was7.2mmol/L.The results showed that the different concentration of H2affected the interaction between microorganisms and microorganisms in soil,that is,the structure of bacterial community. |
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