The growth ofRhizobiumin the Rhizosphere of the host plant

Abstract
Rhizobia pass through the host root surroundings before they infect the root tissue. Therefore, the environmental condition of rhizosphere is one of the greatest factors in the life of Rhizobia in the soil. It was observed that the nodule number produced on the root of the legume is not proportional to the density of Rhizobia inoculated, but nearly constant within some range. The experience presented in the previous paper showed that one or ten cells of Rhizobia inoculated in a test tube were sufficient to produce a number of nodules on the host plants grown in the tube. Such facts strongly suggest the multiplication of Rhizobia in the soil before infection into tissue.