Research and Application of Directed Micro-Ecology in Soybean-Nodulating Rhizobia
China has abundant soybean-nodulating rhizobia germplasm resources,but its application progress is slow,which inoculation area is only 1%～3%of the total soybean planting area in the country.The main reason for the situation is that rhizobia cannot produce spores and have poor stress resistance,resulting in short product shelf life and unstable application effects.In order to diversify,functionalize and differentiate rhizobia products and improve product activity and application effects,a directed micro-ecology(DME)system was used to optimize the culture and successfully achieved the directing cultivation as well as application evaluation of rhizobia and bacillus strains.The optimal culture medium for rhizobia(25.5 mL·L-1 molasses solution,15.2 g·L-1 yeast extract,pH 6.98)was obtained through single-factor experiment of culture medium and response surface method.The medium formulation was applied in DME incubator at proper ventilation volume and incubation time,which made 1 strain of rhizobia(100 L·min-1,20 h)and 3 strains of bacillus(150 L·min-1,14 h)to achieve more than 50-folds amplification of microbial quantities to reach(20～50)×108 CFU·mL-1,and the rate of miscellaneous microorganism contamination was controlled below 5%.Pot experiments showed that the treatments of DME incubating strains were significantly better than the similar treatments of conventional cultured strains in the laboratory,which indicated that the DME incubator could better realize the application performances of functional microorganisms.The combination of rhizobia and bacillus could assist the rhizobia to better deliver its symbiotic function,which was specifically reflected in the increased number of nodules and chlorophyll content in the seedling stage,and the final yield was increased by nearly 20%,compared with single rhizobia strain.The DME system proposed in this study through the control of directed nutrition and growth strategies,allowed the target functional microorganisms to reach application-level yield and purity in a microecological environment containing a variety of microorganisms,achieving the same application performance as pure culture microbial product.It had important significance and application value to promote the industrialization of rhizobia,accelerating the promotion and application of functional strains.
国家科技期刊平台
NSTL
万方数据
维普
