Screening Plant Growth Promoting Rhizobacteria (PGPR) From Rhizosphere Of Grasses And Estabilshing Their Database Management System

In present paper, PGPR from rhizosphere (soil adhering to roots, rhizoplan or surface ofroots and histoplan or interior of roots) of7kinds natural grassland plants (Poa alpigena,Elymus nutans, Achnatherum inebrians, Leymus secalinus, Agropyron cristatum, Stipapurpurea and Roegneria hirsuta) in alpine region of Gansu. Numbers of plant growthpromoting rhizobacteria (PGPR) were determined by using the selective medium. The PGPRstrains were determined based on the measurement of nitrogen fixation capacity,phosphate-solubilization capacity and IAA secretion capacity by using acetylene reductionassay (ARA), the molybdenum blue spectrophotometry, HPLC. In the end, databasemanagement system of PGPR resources was developed. The main results were obtained asfollows：(1) Used conventional bacteria separation methods,201nitrogen fixing bacteria,109inorganic phosphate-solubilizing bacteria and143organic phosphate-solubilizing bacteriahad been isolated from rhizosphere of7grasses in Natural Grassland. In addition to thenumber of inorganic phosphate solubilizing strains from Rhizosphere of Achnatheruminebrians showed " RS> RP> HP", the other strains were showing " RP> RS> HP"distribution trend.(2) All strains had nitrogenase activity but it showed large variation between strains(0.23-751.91nmol C2H4·h-1·mL-1). Only9strains (NGRS11, NGRS13, NZRS14, NZRS6,NZRS11, NCRS5, NCRS11, NLRS9, NCMRS1) showed nitrogenase activity higher than100nmol C2H4·h-1·mL-1.85.57%of201nitrogen fixing bacteria produced alkaline, but12.44%produced acid,1.99%of total strain’s pH was7.0.(3) There were lager differences in109phosphate-dissolving microorganisms capability,phosphate solubilization capacity was between0.47-582.46μg·mL-1, one of the highestconcentrations of strains PCRP5.143strains showed ability to dissolve organic phosphorus,but the difference in ability was large (concentration was0.07-14.76μg·mL-1), one of thehighest concentrations of strains MCMRS4. There were no obvious relationship between theorganic phosphorus strains solubilization capacity and pH (P>0.05), however PKO contrastit (P <0.01).(4) Indole acetic acid content in the92good strains from453PGPR was determined by using HPLC. There were the difference in ability was large (IAA concentration was0.67-43.68μg·mL-1). The producing IAA power of PZHRS6(43.68μg·mL-1), PGRS3(40.87μg·mL-1) were greater than the other strains. It was no correlation between pH of CCM andIndole acetic acid content at0.05levels.(5) Most good PGPR strains growed faster, colony morphology difference was bigger.Vacuum freeze-drying method was used to save fine PGPR, total12strains of nitrogen fixingbacteria,14strains of inorganic phosphate-solubilizing bacteria,12strains of organicphosphate-solubilizing bacteria and6strains producing IAA were saved.(6) Analysing and estabilshing database management system of plant growth promotingrhizobacteria (PGPR). Based on the data collection and analysis of plant growth promotingrhizobacteria (PGPR) in microbiology laboratory of Pratacutural College in GansuAgricultural University, the database management system was designed and developed withAccess2003+Vc++6.0. The system consisted of two modules: basic data systemmanagement and system service management. The former provided functions of data inputabout PGPR. The latter provided a Visual interface, query window and output form window.In addition, it also provided the functions of data modification, data add, data delete and datastatistics and analysis. Totally297strains of PGPR (92strains were identified) inMicrobiology laboratory of pratacutural college in Gansu Agricultural University wereinvolved.