1. “Photoperiodicity” has been recognized in the germination behavior of “Light-favoured Seeds” and “Dark-favoured Seeds”. 2. Many of “Light-favoured Seeds” are “Short Day Seeds”. namely, seeds having in its germination behavior a tendency of “Short Day Plants”. Each species of them has a certain maximum photoperiod favorable for germination. Accordingly their germinattion percentage when exposed to continuous artificial light were lower than the percentage induced by their maximum photoperiod favorable for germination. 3. The favorable photoperiod for the germination of Epilobium covered a wide range of durations (100minutes to 21hours). The seeds of this plant was considered as “Short Day Seeds” in view of the fact that the better germination percentage was promoted by the interruption of the light period with dark intervals than continuous illuminating. 4. “Dark-favoured Seeds” are considered as one form of “Short Day Seeds”. 5. The author couldn't recognized a type which may be called “Long Day Seeds” which show the rate dropped by the interruption of the light period with dark intervals. However, spores of a fern (Athyrium niponicum) obviously presented a charactor of “Long Day Plant”. The writer wish to express my cordial thanks to Professor T. Miwa for his kind guidance during the course of this study and also to Professor S. Hattori and Mr. M. Hasegawa who gave me most valuable suggestions and directions regarding the present work. The writer also extend his thanks to Messrs. T. Oofusa, G. Shimogawara and Miss I. Shihira who rendered assistance througout the experiments, and to Mr. K. Hirano, M. Chihara and Members of local experimental stations of Japan Tobacco Monopoly Agency, and Mr. Goda (Daiichi Gardening Company at Shibuya) who collected and offered precious materials for this study.
1) The localization of phosphorylase in the potato tuber and the process of the starch formation therein were histochemically investigated. 2) In the potato tuber the presense of phosphorylase was demonstrated in all parts of the tissues where storage starch was to be formed, and furthermore in the vascular ring devoid of storage starch. The amount of the enzyme was largest in the actively growing regions, such as tips and buds of the tuber. 3) When various sugar solutions were supplied to the tuber through the cut ends of the stem, starch grains were produced within the cells. They arose from the amyloplasts lying embedded in the cytoplasm, but not from the vacuoles. 4) Among the various sugars tested, sucrose, glucose and maltose were effective for the starch formation, and the high concentration of the sugars favoured this process. From fructose and galactose, no starch was produced. 5) The storage starch grains in the beginning of its formation were still minute in size and occupied only a small part of the cell, but they became to spread into the whole inside of the cell as they grew larger.
The present investigations were accomplished on the vital staining of spermatozoids in eight species of ferns, using the dyes which belong to the monoazo group and others. Beside these studies the influences of hydrogen ion concentration upon the vital staining were also examined. Among the structural portions of the living spermatozoid-body, the ones which are colored are not found in the nucleus, the cilia, and the globule, but found in the cilia bearing band, probably the contents (granules) of the globule and the border-brim. It is supposed that the dyes which belong to one group show no specific staining reaction upon a special portion of the spermatozoid, in other words, no strict and constant relationship can be found between the chemical constitution of the dye and the staining of the living spermatozoid in fern. The living spermatozoid is stained effectively in the weak acid solution and continues its movement in the alkaline solution. The present writer has to express here his most cordial thanks to Prof. Dr. A. Yuasa, College of General Education, Tokyo University and Prof. Dr. H. Ito, Tokyo University of Education, for their sincere instructions and influential advices in the course of this study.
Effects of light intensity and temperature upon the growth rate of Chlorella in cultures of high population density was investigated. It was shown that, by and large, the following equation fits in with the experimental data obtained in the temperature between 7°and 25°C and the range of light intensity between 0.80 and 50.0kilolux. ΔV/Δt=5.3×k/εD log(1+αI/k) where V is the packed cell volume (in ml) per liter of culture, t time of culture (in days), k the maximum growth rate (ΔlogV/Δt in 1/day) at each temperature, α a temperature-independent constant (in terms of 1/day-kilolux), εthe extinction coefficient of the algal suspension (in terms of 1/cm-ml), and I the light intensity (in kilolux). The only disagreement between calculated and observed values was found in the cultures of low temperature (7°C) kept under strong illumination (25-50 kilolux), in which case the cells gradually bleached and eventually ceased to grow for some unknown physiological reasons.
A mating experiment using the twenty-one monosporous mycelia of Collybiavelutipes shows that this fungus is heterothallic and tetrapolar (Table 1). The foregoing result confirms the statements of Vandendries (1923), Zattler (1924), Heldmaier (1930), and others regarding the mating type of the fungus. Twelve months after these monosporous mycelia had been isolated, the spontaneous dikaryotization were examined. Twenty of the twenty-one monosporous mycelia remained in the monokaryotic condition. It is concluded that the fungus is stable for mating type, and that the “hétéro-homothallisme” theory advanced by Vandendries (1925) is hardly applicable to the fungus. In some of the combinations between the single-spore mycelia of C. velutipes, the barrage phenomenon as shown in Figs. 5-9 was observed. The barrage manifested between the monosporous mycelia of the fungus, however, exhibited a very irregular behaviour as shown in Table 2. The theory advanced by Vandendries and his collaborator in Lenzites betulina and other hymenomycetous fungi that the barrage appears only between any two mycelia which are heterozygous in one of the two pairs of mating type alleles independently of the other pair of the alleles cannot be applied to C. velutipes. It is shown to be possible to control the conditions of culture in such a way that the fruit-bodies of the fungus can be developed aseptically in a glass container as desired. Most parts of the present experiments were achieved from April 1950 to March 1951 for the graduation thesis of the University of Tokyo, and it is a great pleasure for the writer to acknowledge his indebtedness to Professor Y. Sinotô and to Dr. N. Tanaka for their cordial leadership during the work. Thanks are due also to Professor H. Ono for his encouragement and very helpful suggestions. He also wishes to thank Professor K. Dan for his correction of manuscript. Further he is indebted to Mr. B. Sakai for making photographs. Finally he wishes to express gratitude to Mr. K. Aoshima, who kindly provided him with the original culture.
(1) Spores of Solieria Mollis (HARV.) KYLIN develop in the same way as spores of Callymenia perforata J. AG. in the same Fam. Callymeniaceae, by means of “Typus discalis mediatus” established by Inoh (1940). (2) Solieria Mollis (HARV.) KYLIN and Chrysymenia Wrightii (HARV.) YAMADA are distinguishable in respects that the former develops by means of “Typus discalis mediatus” and the latter develops by means of “Typus tetraprotocellularis”. although they resemble closely in their external structures.
The plants used in the present studies are the followings. Long-day plants (LP) : oat, pea, white clover, spinach etc. Short-day plants (SP) : soy bean, tobacco, chrysanthemum, morning glory etc. The decrease in the total nitrogen content of the new grown-up leaves of SP during the night is greater than that of LP. This fact indicates that the transport of nitrogen compounds in SP are accelerated in the dark. The elongation of the leaves of SP in the dark is greater than that in the light; but in LP its difference is non pronounced, or rather in some cases the elongation in the light is greater, In SP, however, the elongation of the leaves is accelerated even in the light, when the mature leaves are covered with tin-foil. From these facts it seems probable that, one of the causes of the accelerated elongation of the leaves of SP is that the translocation of nutrient substances from the mature leaves is promoted in the dark. To observe the effects of β-indoleacetic acid on the elongation of the leaves in dark, the basal portion of the cuttings is dipped in the solution of indoleacetic acid. The elongation of the leaves of SP is accelerated markedly by the growth substance; but in the case of LP there is few effects of it. The daily variation of reduced ascorbic acid content in the new grown-up leaves is similar both in the case of LP and SP. It increases during the day and decreases during the night. The ratio of reduced ascorbic acid content in young growing leaves to that in the new grown-up ones is greater in the plants growing vigorously, but when SP have been induced photoperiodically the ratio becomes smaller. One would think that there would be some relations between the shifting in the ratio and the photoperiodic induction in flowering.