Effect of legume seed exudates on the formation of Rhizobium-legume symbiosis

The effect of exudates from germinating lupine and soybean seeds on the development of legumerhizobia symbiosis in the same plants was studied. Treatment with the exudates increased the nodulation activity of Bradyrhizobium sp. (Lupinus) and slowed down the formation of nodules by Bradyrhizobium japonicum 634b. The number of nodules produced by B. japonicum 631 on soybean roots increased when the strain was treated with soybean exudate at a lower concentration. The exudates differently affected nodulation on the primary and secondary roots of the host plant. The formation of symbiosis by B. japonicum 631 incubated with legume seed exudates increased the weight of the green parts of plants at the bud stage.