ADSORPTION OF BRADYRHIZOBIUM JAPONICUM AND ROOT HAIR CURLING IN NONNODULATING (RJ1 RJ1) SOYBEAN PLANT

Adsorption of Bradyrhizobium japonicum and root hair curling in the rj 1non-nodulating mutant of soybean were studied to determine the stage of blockage in the nodulation process. The numbers of bacteria detected in the homogenates of roots of rj 1and wild Rj 1soybean were similar 2, 3, and 5 days after inoculation. The relationships between the density of bacteria inoculated and the bacteria adsorbed onto roots of rj1and Rj 1soybean were hardly different. Fluorescence microscopy revealed the polar attachment of bacteria to the root hair in both rj 1and Rj 1soybean. The percentage of root hair curling was reduced in the roots of rj 1soybean, as compared with Rj 1soybean. These results indicate that in the rj 1mutant of soybean blockage occurs at the stage of root hair curling and not at the stage of bacterial adsorption. © 1990 Taylor & Francis Group, LLC.