Characteristics And Growth-promoting Effects Of Culturable Endophytic Bacteria Of Xanthoceras Sorbifolia Bunge With Tumor Roots

With the development of biomass energy,Xanthoceras sorbifolia is a woody oil tree species,and its development has received more and more attention.Xanthoceras sorbifolia Bunge with the tumor root were discovered,the endophytic bacteria which isolated from the tumor root were purified and identified.Endophytic bacteria ability which produced siderophore,secreted indole-3-acetic acid(IAA)and dissolved phosphorus were adopted.A strain of Pseudomonas sp.XSB5 and a strain of Yorkella sp.GG10 was used as a test strain to treat the seeds and seedlings of Xanthoceras sorbifolia.In order to analyze the growth-promoting effect of endophytic bacteria on the seedlings of Xanthoceras sorbifolia.The aim is to provide a theoretical basis for the the development and utilization of rhizosphere microbes,Results are as follows1.Strains were isolated from the tumor roots through morphological and molecular identification,and they were named XSB1-XSB9,of which 6 strains belonged to Bacillus sp.,2 strains belonged to Brevibacillus sp.,and 1 strain belonged to Pseudomonas sp.2.A11 9 strains produced siderophores;strains XSB3,XSB4,XSB8,and XSB9 were extremely high-yield,the siderophores unit is between 80%and 100%,and strains XSB5 and XSB6 were is high-yield,the siderophores unit is between 60%and 80%.The strains with high yields accounted for 66.7%of the tested strains.Nine strains secreted IAA;the concentration of IAA secreted by the strains that contained tryptophan was between 15-50 mg/L,and the concentration of IAA secreted by the one strain without tryptophan was between 10-35 mg/L,the ability of strains XSB2,XSB3,XSB4,XSB5 and XSB9 to produce IAA was significantly different from that without tryptophan(P<0.05).The synthesis amount of strain XSB5 was about 50 mg/L;All 9 strains had some ability to dissolve phosphorus.The concentration of phosphate in the solubilizing strains,XSB1,XSB2,XSB4,and XSB5,were significantly higher than that in the other strains(P<0.01),and the concentration of phosphate solubilizing was between 50-90 mg/L,and the ability to dissolve phosphorus could be increased by 19-29 times.In summary,the strains XSB4 and XSB5 have strong ability to dissolve phosphorus,produce IAA and produce siderophores,and it is worthy of being used as an alternative strain to promote growth and promote growth mechanism.3.The root and aerial part biomass of Xanthoceras sorbifolia was significantly increased after treatment with XSB5 bacterial solution(P<0.05).After treatment with GG10 bacterial solution,the root and aerial part biomass of Xanthoceras sorbifolia were increased,and the root part biomass increased significantly(P<0.05).4.The accumulation of N,P,and Mg in Xanthoceras sorbifolia treated with XSB5 was significantly increased than that of the control(P<0.05).After treatment with XSB5,the accumulation of Fe in Xanthoceras sorbifolia were significantly higher than the control(P<0.05).After treatment with GG10,when treated for 30 minutes,the accumulation of Fe in the Xanthoceras sorbifolia was significantly increased by 23%,when treated for 60 minutes,there was no significant difference from the control.5.The content of available N and P in the culture substrate was significantly increased compared with the control after treatment with GG10 bacterial solution.When treated for 30 minutes,it increased by 34%and 16%respectively.When treated for 60 minutes,it increased by 32%and 22%respectively.After treatment with XSB5,the available N and P contents only increased significantly when immersed for 60 min,which increased by 18%and 31%,respectively.The available Mg and Fe contents were not significantly different from the control.It indicated that the inoculation of these two endophytic bacteria could affect the change of mineral elements in the culture substrate,increase the uptake of mineral elements by Xanthoceras sorbifolia,and change the translocation factor of mineral elements upwards,thus promoting the growth of Xanthoceras sorbifolia.6.There was a significant positive correlation between the accumulation of N,P,Mg and Fe mineral elements in Xanthoceras sorbifolia(P<0.01),and there was a significant positive correlation between dry weight and mineral elements of N,P,Mg and Fe(r=0.941,0.990,0.981,0.758,respectively)(P<0.01).