Abstract
1. The present paper deals with the results of the experiments which were made to ascertain the existence of plant hormone in dry vaccine B of the rice blast fungus (Piricularia oryzae Cavara 2. The writer used the various kind of cocentration of dry vaccine B as the test solution, and distilled water, 2, 4-D, MCP as the control. The writer could ascertain the existence of minute quantity of the plant hormone in 0.5 % dry vaccine B of the rice blast fungus by Went's Pea Test Method. 3. The existence of the plant hormone (see Fig. 1, 2) was ascertained in the chloroform and ether extracted juice of dry vaccine B by Went's Pea Test Method. 4. The existence of the plant hormone in dry vaccine B was ascertained by the sand culture method (contained dry vaccine B), through the growth ratio (see Table 1) in the length of roots and stems of radishes and up land rice plants, especially, through the abnormal growth (hypertrophy, see Fig. 3 or constricted) of radishes. 5. The paper chromatograph method was used to detect the kinds of plant hormone and it was found out something resembling to β-indol acetic acid (see Table 2, 3). 6. Such plant hormone might be produced by the metabolism of rice blast fungus itself. In case the ricc seed is treated with dry vaccine B, it may be absorbed in the seed and stimulate the cells of embryonal tissues of it. It is presumable that this stimulus has made good effects on the germination of the seeds, and afterward, on the growth, the yield and the percentage of diseases.
