| Abstract: | Cross inoculations were made with Frankia spp. from the nodules of non-leguminous plants belonging to different families, genera and species. The results showed that there are no apparent host specificity in these strains. Under general cases, many strains can nodulate plants in different families, genera and species, but there also are some special results. Both infective ability of the same strains on diffierent host and the different strains on the same host are different. Different isolates from the same host plant were found in certain cases to have various degrees of infectivity. If the original host plant was replaced by others, both these Frankia infective ability and nitrogenase activity in new symbiotic system were lower. The strains that are higher N2-fixing activity in the nodules of the original host also possess stronger N2-fixing activity in the nodules of other hosts. Under test condition, there are positive correlation between the number of the nodules of host plants and N2-fixing activity of the root nodules. The morphology of the spores of the strains in the nodules of new host plant also change more or less. |
