Font Size: a A A

Studies On The High-density Cultivation Of Phosphobacteria And Acacia Rhizobia And Analysison 16S RDNA Sequence Of Acacia Rhizobia

Posted on:2006-07-10Degree:MasterType:Thesis
Country:ChinaCandidate:J H ShangFull Text:PDF
GTID:2120360182961511Subject:Biochemistry and Molecular Biology
Abstract/Summary:PDF Full Text Request
As a Leguminosae tree seed, Acacia has been increasingly attached importance to because of its accrete nitrogen fixation.Studies have shown about 52%-66% of the azote element originate from the nitrogen fixation of Rhizobium in Acacia auriculaeformis and Acacia mangium .Reseaches on Acacia have all concentrated on the interaction between both sides of nitrogen fixation, and there are no report on the optimized culvivation of Acacia Rhizobium ,who exerts the function of nitrogen fixation in the accrete complex.Making use of dissimilation of phosphor of microbes to alleviate the shortage of phosphor in the soil has attracted the attention of researches inland and overseas.This study we engaged was concentrated on the optimization of cultivation condition of Phosphobacterium and Acacia Rhizobium ,who can benefit functions of each other,the results provide premise and lay base for futher development microbal fertilizer with both the function of nitrogen fixation and phosphor dissimilation. Sequencing and analysis of 16S rDNA gene of three strains of Acacia Rhizobium was also included in the study to make certain the phylogenetic relation of them to other type strains of all known rhizobia.1) .The growth curves of AJ018 , YM2 and MZ Acacia rhizobia and 217 phosphobacteria were drawn in four media in this study. The results showed that these four strains could both grow well in BSE medium. Based on the conventional media, the optimized media of AJ018 , YM2 and MZ rhizobia and 217 phosphobacterium were obtained from orthogonal tests. Furthermore, the optimized media were testified to be more suitable for the growth of all of the strains, with more live bacteria, by the growth curves got afterwards.2) .The process conditions,such as inoculum age,inoculum volume and so on were optimized by shake flask method. The relationship between pH level, phosphate dissolving and bacterial growth ability was also discussed in the study on the phosphate-dissolving ability. The study of nitrogenase activity by Acetylene reduction method showed that MZ and YM2 had comparatively high nitrogen-fixation activity in three Acacia rhizobia, which reached 0.963μg.mL-1.d-1 and 0.280μg.mL-1.d-1.3) .This part involved in the production of rhizobium MZ and 217 phosphobacterinm inoculant.The quantity and Survival ratio of 8 solid inoculants were compared during different time . The results showed that conservation effection was poor,among those 8 solid inoculants ,Calcium Carbonate was best,whose quantity and Survival ratio were 1.38xlO5, 10.1% respectively.while 217 strain conservation effection were good in those 8 solid inoculants,especially Kaolin, zeolite powder and Calcium Carbonate.4) .Those sequence were compared with that of type strains of all known rhizobia and related bacteria.An unrooted phylogenetic tree was produced.In this tree,strains AJ018 and MZ, B.japonicum, B.liaoningense, B.elkanii constituted Bradyrhizobium branch.Within this branch,the similarity values of 16S rDNA sequence between strain AJ018 and B.japonicum, B.liaoningense were 95.1%,96.1% respectively,and the similarity values of 16S rDNA sequence between strain MZ and B.elkanii were 98%. All simiarity values was more than 95%,this indicated that these species should belong to the same genus.The values of homology between YM2 and other type strains of all known rhizobia was less,it is worthy of further reseach.
Keywords/Search Tags:Acacia rhizobia, Phosphobacteria, Media optimization, Nitrogenase Activity, Phosphate-dissolving ability, Inoculant, 16S rDNA sequence
PDF Full Text Request
Related items