The phosphorylase content of potato tubers was measured in the course of their development. It was found that the amount of phosphorylase increased rapidly with the development of the tuber until the tuber grew to about 50g in weight. Thereafter the increase in enzyme content dropped gradually and nearly ceased when the tuber attained the weight of about 100g. It became probable that the increase in enzyme activity might be attributed chiefly to that in the “cortex with buds”. Sincere appreciation is expressed to Prof. T. Miwa, of the Tokyo University of Education, for his valuable advice and criticism during the course of this investigation and in preparation of this manuscript.
1) In the protoplasmic streaming of Chara, we can see a difference between the flowing rate of upward streaming and that of downward streaming. This is true in respect to most of the endoplasm, except that which is in direct contact with the cortical gel. The rate of the latter streaming is not affected by gravity. 2) By means of a centrifuge-microscope, we find that the centripetal flow of the endoplasm stops under the influence of centrifugal acceleration amounting to 40×g. But the endoplasm adjacent to the cortical layer requires five times as much centrifugal acceleration as the above in order to be brought to a standstill. 3) The mechanism of the motive force generation exists only at the boundary region between the cortical gel and the endoplasm, and all the other portions of the endoplasm are thought to be passively driven by the force generated at this region.
In this report the effect of inorganic nitrogen containing NH4+ and NO3- upon the perithecial formation in Red Bread Mold, Neurospora crassa, was studied. The nitrogen source containing NH4+ and NO3- was effective for the perithecial formation rather than the nitrogen source containing each one of either NO3-, NO2- or NH4+ respectively. The culture filtrate produced from the basal medium containing NH4+ and NO3- as nitrogen source showed the maximum perithecial formation effect when the medium was supplemented with the richer concentration of NH4+ than that of NO3-.
The reversion rates per unit time of homocysteineless strains of Ustilago maydis were determined at seven or eight temperatures. The temperature coefficients were 3.9, 2.2 and 1.8 and activation energies, 0.92, 0.65, and 0.42ev respectively. The relationships between reversion rate and activation energy, and between frequency factor and activation energy were analyzed. It was suggested that the various mutants have a pseudoallelic nature. The authors wish to express their thanks to Dr. F. J. Ryan for his helpful advice and suggestions given in this work and thanks are also due to Dr. D. D. Perkins who has kindly supplied the original strains of Ustilago maydis.
1. The karyotypes of 4 species of Aster from Hokkaido and Saghalien are reported. 2. There can be found no difference between the karyotypes of the four taxa and those of the corresponding relatives in Honshu.