抄録
In this paper, the results on the relation between host plants and the classified strains of rhizobia in the cowpea group are described. The meaning of classification tried in part I is more evident in these results than in those presented in the previous paper. Although the so called host specificity is evident, the host plants are divided into two main groups according to their relation to the strains of type A. One of the two symbioses effectively with the strains of type A, and the other does not so with them. Since not all strains belonging to type A behave in similar manner, they must be subdivided, at least, into two subtypes from the point of symbiotic relation to hosts except Arachis and Centrosema, to which no strain of this type is effective. It is found that the subdivision of type A in such cases accords well with that depending upon the nodule producing power on soybean. In general, among the strains of type A, those which do not form nodules on soybean are effective to wide range of host. Similar phenomena seem to be found among strains of type B, though not so clearly. It is curious that among the plants used in this study, few of them show effective association with the strains of type B, in spite that this type of strain is usually considered to be typical as cowpea bacteria. No effective association is found in the case of type E or D. Considered from the strain variation, it is note-worthy that some hosts are able to symbiose effectively with diverse strains of rhizobia. Vigna sinensis or Tephrosia maxima is presented as an example. Concerning the results that different types of strain show similar effect to some hosts, whether or not such similarity is influenced by the environmental conditions remains to be studied.
