Comparative analysis of symbiotic phenotypes of soybean 'Tianlong 1' with two different rhizobia and co-inoculation at different developmental stages

摘要

Symbiotic nitrogen fixation between soybean and rhizobia, which directly cata-lyze reduction of atmospheric nitrogen into ammonia, has critical importance in agricultural economy and environment. However, soybean symbiotic nitrogen efficiency, which changes with growth stage, largely relies on symbiotic host-specificity and nodule development. In this report, symbiotic phenotypes of soybean 'Tianlong 1' with different inoculation (inoc-ulated with Bradyrhizobium japonicum strain 113-2, Sinorhizobium fredii USDA205 and co-inoculated with 113-2 and USDA205) were comparatively studied at different develop-mental stages. Without additional nitrogen, chlorophyll content, above ground fresh weight, plant height, nodule number and nodule dry weight changed with different rhizobia at vari-ous developmental stages. 113-2 had more advantages than USDA205 in promoting plant growth and nodulation. Nodulation morphology of co-inoculation was more similar to 113-2 than USDA205. Competitive nodulation between two rhizobia promoted plant growth, which had significant agricultural application prospect. For the first time, this study provided evidence for co-inoculation with different rhizobia having positive effect on plant growth, and shed new light on the competitive relationship between different rhizobia.