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1. In order to test the buffer action of roots, the adjacent segments of excised rice roots were separately submerged in acid wellwater. 2. The difference of buffer action between the roots which were cut in air and in wellwater was tested. The buffer action of the former was higher than the latter, due to the loss of cell sap from the cut surface of roots before submersion in the acid water. 3. The buffer action decreased after desiccation of roots before submersion in the acid water. 4. The buffer action was distinctly found in the roots which were treated with chloroform vapour for 10 minutes, but it was scarcely seen in the foots which were treated with 75% alcohol solution for 5 miniutes. 5. The buffer action of the apical zone was visible at 2°C, and 25°C., but the action was less at 2°C. 6. When CO2 gas was bubbled through the acid water used in these experiments for 1∼5 hours, the pH did not change. 7. It is presumed that the buffer action should have become functional by some substance which is formed in the process of metabolism of living cellls and penetrated througth the root tissue.

1. The adjacent segments of excised roots were separately submerged in acid wellwater (e. g. pH 3.0, 3.4, or 4.0) for 20 hours. The pH of the wellwater was measured by the chinhydron electrode method at the beginning and end of every experiment. 2. At the end of every experiment the pH value usually reverted in the nutral (pH 7) direction by the buffer action of roots. 3. The buffer action was highest in the apical segment of the root and decreased in those more remote. 4. The buffer action differed with the species or varieties of the plants.

Exp. I. It was the problem whether the growing small tillers check the ripening process in fruitful stems or not in wheat. 1) From the results, the average weight of heads, 1, 000 grains-weight and total weight of grains were found to increase when the small tillers were cut or pressed down at the head-formation stage. The effect of cutting-off was especially remarkable. Exp. II. The purpose was to know of the interrelation between weak and strong tillers at the stage of vegetative growth in wheat by means of radiophosphorus. 1) At the tillering stage, P32 absorbed through roots were transferred in larger amounts to the weak tillers than to the strong ones. Among the tillers formed at the same time, the amount of P32 transferred was larger to the lower tillers than to the upper. P32 absorbed through leaf surface of either weak or strong tillers was transferred apparently more to the weak tillers. But, when P32 was absorbed through leaf, it was transferred more to upper tillers than to lower ones among the tillers growing at the same time. 2) At the head-formation stage, the translocation of P32 absorbed through both roots and leaf showed the same tendency as that in the case of 1). But the difference between weak and strong tillers was smaller. Therefore, it seems that the weak tillers seize nutritives away from the fruitful stems during the vegetative growth period checking the development of the latters.

Between varieties, rice, wheat and barler plants were grafted. Unions between the scions and the stocks of which tillers were cut off were formed at the intercalary meristem. All the roots of scions which abpered after grafting were cut off. In successful grafting, the callus formed the parenchymatbus union and ther the vascular union was established. Radioactivephosphorus (P32) that absorbed through the leaf of the stock transferred to the young ear of the scion.