Studies on nodulation of soyabeans in Egypt. II. Effect of seed-diffusates on Rhizobium japonicum.

The growth inhibition zones of R. japonicum (E 45) by either surface-sterilized seeds or autoclaved seeds (as well as dicotyledones, cotyledone, or seed coat) of Harosoy soyabean cultivar indicate the presence of antibacterial substances. Several physical and chemical seed treatments were done in a trial to eliminate or decrease the observed inhibitive effects of the seed-diffusates in order to obtain successful nodulation. The antibacterial substances are thermostable (121 degrees C), water-soluble or partially insoluble, exist in the whole seed and could be inactivated by certain chemical seed treatments as well as by germination for 12 hrs. or more before inoculation.