Isolation And Identification Of Hydrogen-oxidizing Bacteria Near Mung Bean Rhizosphere And Study On Their Plant Growth Promoting Mechanism

In recent years,both at home and abroad on studies on the Plant Growth-Promoting Rhizobacteria(PGPR),Hydrogen-oxidizing bacteria belong to the rhizosphere bacteria,it can promote the growth of the plant. Therefore,also widely watched of hydrogen-oxidizing bacterium.However, a late start.This article on legume in Shaanxi region conducted a study of hydrogen-oxidizing bacteria in rhizosphere of mung bean.The content and results were as follows:Using gas-cycle incubation system (H2treatment system)device to capture3batches of soil samples for enrichment,and respectively measured water content,pH and soil enzyme activities and soil organic matter content.Results show that after the H2-rich,soil enzyme activity and soil organic matter content of soil samples II improve significantly.There fore, selection of soil samples II as the experimental study on material.After enrichment of soil samples II in airtight containers,using H2treatment system and plate coating method,on the separation and purification of mineral salts in solid culture medium gets26strains of bacteria.Gas chromatographic method for measuring strain of hydrogen oxide, results showed that9strains of bacteria hydrogen absorption value greater than2.44×10-4mol·L-1. For example, LD2,LD6,LD7,LD9,LD13,LD17,LD18,LD21,LD24. Hydrogen absorption value of strain LD6up to17.13×10-4mol·L-1,belonging to the dominant strains.According to the eell, colony form and biochemical characteristics,we identified the strains as follow, Pimelobacte, Pseudmonas, Micrococcus, Brachbacterium, Aeromonas, Nocardia.We studied the optimal culture condition of strain LD6,which showed that the optimal temperature was30℃,the optimal carbon source was glucose and the optimal pH was7.0.In the experiments of the9hydrogen-oxidizing bacteria effect on wheat,the culture plate showed that strain LD6,LD9and LD21had strong ability to promote the growth of wheat.The length of roots respectively increased by25.9%,22.2%and21%compared with the control. The length of sprouts increased by21.9%,18.8%and17.3%. The fresh weights and the dry weights were25.1%,222%,19.2%and26.1%,21.4%,16.7%.Thin layer chromatography was used to find out the9strains which could have ACC deaminase,and the result showed that strain LD6consumed the ACC and had ACC deaminase.16SrDNA sequence of strain LD6was analyzed and built the phylogenic tree.LD6and Pseudomonas pseudoalcaligenes IAM12411similarity in the highest,with the sequence identity of89%.So judged LD6is Pseudomonas pseudoalcaligenes.