Abstract
In this part the suitability of asparagine, ammonium salt, nitrate, and nitrite for the growth of rhizobia was examined. Yeast water (0.5% Vol.)-mannitol-mineral salt solution was used as a basal medium, because most of the rhizobial strains were unable to grow in a simple synthetic medium, although strains from Robinia, Lotus, Sophora, Amorpha, Caragana, Astragalus, Sesbania, Dalea, Indigofera, Styphnolobium, and some strains of soybean-and cowea-group were able to grow in it. The root nodule bacteria are divided into the following groups on the basis of the kind of utilizable nitrogen compounds. 1. Asparagine, ammonium salt, nitrate, and nitrite are all effective. ……strains from pea group, clover group, bean group, alfalfa group, soybean group, cowpea group, Sesbania, Mimosa, Leucoena, Dalea, Styphnolobium, Sophora. 2. Asparagine, ammonium salt, and nitrate are effective. Nitrite is ineffective. (Not all strains in this group are unable to attack nitrite.) …………strains from alfalfa group, lupine group, soybean group, cowpea group, Indigofera. 3. Asparagine and ammonium salt are effective. Nitrate and nitrite are ineffective. ……strains from cowpea group, Indigofera, Astragalus, Lotus, Caragana, Amorpha, Robinia. 4. Ammonium salt, nitrate, and nitrite are effective. Asparagine is ineffective. …… strains from bean group, Sesbania, Vicia (nipponica). 5. Ammonium salt and nitrate are effective. Asparagine and nitrite are ineffective. ……strain from soybean group. 6. Asparagine is effective. Ammonium salt, nitrate, and nitrite are ineffective. ……strains from cowpea group. Not few strains from lupine-, soybean-, cowpea-group, and Sesbania seem to bring about the loss of nitrogen in nitrate or nitrite medium.
