On the Ovary and Ovule Development in Nicotiana tabacum induced by α-Naphthaleneacetic acid

Few reports have been published concerning the effect of chemicals in stimulating the development of ovule and embryo. YASUDA (1940) reported that by injection of a growth promoting substance into the ovary of Petunia, when the stimulated cells were embryonic, cell division took place, while if the cells were fully developed, the growth of the cell-membrane alone was stimulated. OVERBEEK, CONKLIN, and BLAKESLEE (1941), testing many chemicals, in a wide range of concentrations, for their effect upon ovule development, reported that auxins injected into the ovaries of Datura induced the development of parthenocarpic fruits with enlarged ovules which contained pseudoembryos originated from the integuments. They suggested that other plants might be found in which similar treatments would stimulate the formation of true embryos. In order to examine the possibilities of artificial parthenogenesis suggested by the reports mentioned above, the present writer has carried out a few experiments in this line. The present report deals with injections of a growth hormone into the ovaries of Nicotiana tabacum L

Leaf Spodograms in the Genus Aegilops : I. General Morphology (MATHEMATICS AND NATURAL SCIENCE)

Spodograms of the leaves of Aegilops species were investigated. The silicified portion of the epidermis consists of elongated, small, quartziferous, spiniferous and round cells, and hairs. Overlying the veins are found to the highest degree silicified elongated, small, quartziferous, and spiniferous cells. Overlying the parenchyma rather weakly silicified elongated and small cells are chiefly found. In certain species the epidermis lacks in a few kinds of cells mentioned above

Taeniophyllum aphyllum (MAKINO) MAKINO に関する研究花柄・根及び葉の構造(A. 自然科学)

Taeniophyllum aphyllum (MAKINO) MAKINO, one of the epiphytic orchids in Japan, was investigated morphologically. The mature root has dorsiventral structure and the under side adheres to the substrate with four-layered velamen. The cortex contains chloroplasts. The central cylinder is a typical root-form. The young plant has one leaf, which is triangular in cross-section, and the basal surface is adjacent to the substrate, while the other sides serve for assimilation. The epidermis is provided with stomata, which are similar in structure to those of the other orchid-plants. The epidermal cells and the vascular bundle of the leaf differ from those of the flower stalk or the root, but resemble those of the other orchids. The leaf has no hairs, and no velamen nor velamen-like tissue

Contents of Embryo Factor in Developing Seeds of Datura and Lupinus (A. NATURAL SCIENCE)

1. In the seeds of Datura tatula and Lupinus, the content of embryo factor increases with the development of the seed. A rapid growth of the embryo occurs two or three days after a rapid increase of the factor. 2. The highest content of the factor is observed at the time of the most active growth of the embryo. 3. In the older seeds the content of the factor decreases, but in the fully mature Lupinus seed a considerable amount of it is found. 4. The embryo factor is found also in placenta and fruit coat of Datura and in pod of Lupinus. The authors are indebted to Prof. S. Imamura, Kyoto University, for his guidance and counsel during the course of this study

Some Factors Affecting the Growth of Young Embryo in Vitro (A. NATURAL SCIENCE)

1. For the growth of young embryos of Datura tatula in vitro, the optimum concentration of agar in the medium is 4.5g/l. 2. The optimum temperature is 35℃. 3. No effect of illumination of fluorescent lamps on the growth of the embryo is observed. 4. Embryos cultured on the agar surface of the medium develop the root more rapidly than those submerged in the medium do. 5. Among carbohydrates tested, sucrose is the best carbon source. Galactose, glucose, mannose, and raffinose are unfavorable. Fructose, lactose, maltose, mannitol, and xylose do not support the growth of the embryo. 6. The optimum pH value of the medium is 6.2. 7. Thiamine hydrochloride, riboflavin, para-aminobenzoic acid, folic acid, uracil, adenine sulfate, IAA, kinetin, and IAA-kinetin combinations have no growth-promoting activity in the young Datura embryo. A growth factor mixture (thiamine hydrochloride, pyridoxine hydrochloride, nicotinic acid, and glycine) added together with NH_4NO_3 is slightly effective. 8. Casein hydrolysate and vitamine- and salt-free one stimulate strongly the growth of embryo, peptone considerably, and tryptone and yeast extract slightly. Autoclaved DNA and RNA are rather inhibitory. The authors are indebted to Professor S. Imamura and Assistant Professor M. Hamada, Kyoto University, for their guidance and counsel during the course of this study

Growth-Promoting Factors in Young Lupinus Seeds (A. NATURAL SCIENCE)

1. The present study is concerned with cytokinin and embryo factor in young Lupinus seeds. 2. Partial purification of these factors was carried out. 3. The silver-precipitated fraction of the Lupinus extract stimulates cell-division of calluses of tobacco and carrot. It is promotive to the growth of radish leaf, and inhibitory to the degradation of chlorophyll of radish cotyledon. 4. Embryo factor and cytokinin in the Lupinus extract have different Rf values on paper chromatogram, indicating that they were different substances

Cytokinin Activities of Dihydrozeatin in Several Bioassays (A. NATURAL SCIENCE)

(±)-Dihydrozeatin was tested for its cytokinin activities in several bioassays and compared with different cytokinins. Dihydrozeatin stimulates the growth of tobacco callus at the concentrations of 10^-10^M with the optimum at 10^M, shoot development on tobacco callus at 10^M with 2×10^M IAA, the germination of lettuce seeds at 10^-10^M, the growth of radish leaf at 5×10^-5×10^M, and the development of lateral buds in pea seedlings at 5×10^M. This cytokinin inhibits the elongation of pea stem segment and delays senescence in detached wheat leaves at 10^-10^M. Dihydrozeatin is less active than zeatin and N^6-(isopentenyl) adenine (2iP) in these bioassays used, but it is of stronger activity than kinetin in the growth of tobacco callus and radish leaf and less effective in the germination of lettuce seeeds and the retention of chlorophyll

Occurrence of a Novel Cytokinin in Persimmon Fruitlets (A. NATURAL SCIENCE)

Ethanol extract of persimmon fruitlets (Diospyros kaki L. cv. Hiratanenashi) contains cytokinins which stimulate strongly the growth of tobacco callus tissue in vitro. One of these cytokinins was purified with n-butanol extraction and ion exchange columns, and compared with known natural cytokinins in paper chromatography with several solvent systems. It was revealed that this cytokinin was very closely related to zeatin, but apparently distinguishable from it. Results indicate an occurrence of a novel cytokinin in the persimmon fruitlets

日本産ラン科植物の染色体数(第 1 報)(数学及び自然科学)

Chromosome numbers are reported for 38 species and 4 varieties of the family Orchidaceae in Japan. Preparations were made from root tips by the modified squash method (Mutsuura and Nakahira, 1956). The results are summarized in table 1,in which 20 species and 3 varieties are reported for the first time. Chromosome numbers of 18 species and a variety are reconfirmed, but Calanthe reflexa (2n=42) is different from the previous number (2n=40). In the species of Calanthe tricarinata, one triploid plant (2n=60) is found