RhizobiumStrain Effects on Nitrogen Transport and Distribution in Soybeans

Publisher Website
Google Scholar
Abstract
Neves, M. C. P, Didonet, A. D., Duque, F. F. and Dobereiner, J. 1985. Rhizobium strain effects on nitrogen transport and distribution in soybeans.—J. exp. Bot. 36: 1179–1192. The role of six Rhizobium strains in the nitrogen metabolism of soybeans (Glycine max Merril) was studied under glasshouse and field conditions. The strains could be divided into two groups, group I which produced a large nodule mass with relatively low efficiency and group II which produced less nodule mass but which fixed the same amount of nitrogen. Plants inoculated with group I strains remobilized nitrogen faster from leaves but also lost more nitrogen in senesced leaves. Although the total nitrogen transported in the xylem was similar for all strains, plants inoculated with group I strains contained less nitrogen in ureides in the xylem sap during the whole growth cycle. This difference was reflected in the nitrogen partitioning within the shoot, and smaller nitrogen harvest indexes were observed in these plants than in those inoculated with strains of group II. The role of ureides in the nitrogen partitioning and grain yield was confirmed by the significant correlation between mean ureide content in xylem sap and nitrogen partitioning or yield. Further, nodules formed with group I strains evolved more hydrogen than those formed with group II strains and the possible significance of this is discussed.