The Japanese Journal of Genetics
Online ISSN : 1880-5787
Print ISSN : 0021-504X
ISSN-L : 0021-504X
Volume 29, Issue 5-6
Displaying 1-7 of 7 articles from this issue
  • SHUN OKUNO, SHIZUE NAGAI
    1954 Volume 29 Issue 5-6 Pages 185-196
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    Twelve different chromosome numbers were found in eighteen plants of B. tuberohybrida examined (Table 1). Meiotic chromosome configurations were studied in seven plants, No. 5, 3, 9, 27, 22, 21 and D (Table 2). They were found to be striking polymorph with respect to the nuclear organization.
    In a plant of B. tuberohybrida under investigation, a very peculiar type of abnormal meiosis was noted. It is characterized by the formation of multiple plates posterior to the first metaphase. And during the course of this division, a tendency of one genom to behave as an individual entity is shown.
    In Begonia, chromosomes in pollen grain division were first demonstrated by the present study. Several different chromosome numbers were found. The results of chromosome counts were as follows; 28, 29, 30, 31, 35 and 10.
    Expence of the present study was partly defrayed by a Grant in Aid for Fundamental Scientific Research of the Ministry of Education.
    Download PDF (1635K)
  • III. COMPETITION AND SPACING IN ONE DIMENSION
    KAN-ICHI SAKAI, YASUO SUZUKI
    1954 Volume 29 Issue 5-6 Pages 197-201
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    Download PDF (262K)
  • VII. EXTERNAL CHARACTERS, FERTILITY AND SOMATIC CHROMOSOMES OF T. PYRAMIDALE×S. CEREALE F2 PLANTS
    GOICHI NAKAJIMA
    1954 Volume 29 Issue 5-6 Pages 202-204
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    1. The number of somatic chromosomes of TpyRF2 plant was counted to be 41, 42 and 43 according to individuals.
    2. Considering from the number of somatic chromosomes of the F2 plant, the fertile gametes of F1 plant may have 20-23 chromosomes.
    3. In general, the external characters of the F2 plant are more heterotic than those of the parents.
    4. Seed fertility of the F2 plant has higher percentage than that of the F1 the individual having amphidiploid number of chromosomes having highest percentage.
    Download PDF (690K)
  • V. THE BEHAVIOR OF CHROMOSOMES IN THE MEIOSIS OF TETRAPOLOID RICE VARIETIES AND THEIR HYBRIDS
    H. OKA, S. C. HSHEH, T. S. HUANG
    1954 Volume 29 Issue 5-6 Pages 205-214
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    1. A number of tetraploid rice varieties and their F1 hybrids were observed with regard to the behavior of chromosomes in pollen mother cells. It was found that in a greater part of cells every four homologus chromosomes formed either one quadrivalent or two bivalents, but a few univalents were also seen.
    2. The average number per cell of quadrivalent and bivalent chromosomes differed with the variety or in hybrids with the combination of varieties, and ranged from 5 to 9 or from 5 to 12 respectively.
    3. It was generally found that in intervarietal hybrids the numbers of quadri- and univalent chromosomes were less numerous than in auto-tetraploid varieties. Numerically unequal division at anaphase was also less frequent in hybrids. However, hybrids between mutually remote varieties and between close ones showed no significant difference in this tendency.
    4. Hybrids were generally higher in fertility. Among the hybrids or the parental varieties, no significant correlation was found between the number of quadri- or univalent chromosomes and fertility.
    5. The improvement of chromosome behavior in hybrids may be due either to selective pairing of chromosomes derived from the same parent or to a complementary effect of parental genes. It seemed difficult, however, to evaluate the relative probability of these two hypotheses from these cytological data.
    Download PDF (475K)
  • Y. WATANABE, K. MUKADE
    1954 Volume 29 Issue 5-6 Pages 215-222
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    By backcrossing to the F1s of (Triticum Timopheevi×T. vulgare) with their parents, 24 BF1 plants were obtained, of which 21 plants were raised by the pollen of T. vulgare. And our cytological observations were carried out principally on them.
    Consequently it ws found that these 21 BF1 plants were consisted of the plants having 2n=37 (1 plant), 2n=38 (4 plants), 2n=39 (7 plants), 2n=40 (4 plants), 2n=41 (4 plants) and 2n=42 (1 plant) respectively, the mode of 2n chromosome number being in 39. From this, it can be infered that of the gametes formed in F1 plants, these having 18 chromosomes play best their function as female.
    Moreover, the behaviour of chromosomes at MI of P.M.Cs. was observed somewhat in detail on the 7 plants with different chromosome numbers, of which 1 plant having 2n=30 chromosomes was the one backcrossed by Timopheevi (see Table 2 and 3).
    As a result of these observations, it became evident that by backcrossing the numbers of univalents and multivalents in BF1 plants decreased considerably, but the numbers of bivalents, especially of closed bivalents increased in comparison with those in F1s, and therefore the fertility of BF1 plants was raised strikingly.
    Download PDF (980K)
  • II. NUCLEAR DIVISION
    A. YUASA, T. HIRANO, O. SUZUKI
    1954 Volume 29 Issue 5-6 Pages 223-227
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    In the present study, Mycobacterium 607 is taken as the material. Thebacteria are cultured on Oka-Katakura's culture-medium. The bacteria have a tendency to become spherical when they grow old on the same culture-medium. Young bacteria elongate after several nuclear divisions and then divide by fission into several individuals, each of which has one nucleus respectively. They show branches which contain one nucleus or several nuclei and the branches also cut off from the mother body. Sometimes little processes, each of which contains a nucleus, are formed at various portions of the long bacterium, cut off from the mother body and become new individuals.
    The nucleus is stained with nucleus-stdining dye-solution and shows positive reaction to Feulgen's nucleal staining. When treated with DN-ase the bacterium stains faintly with the aqueous solution of gentian violet. One nucleus is seen in every cell of Mycobacterium 607, but sometimes several nuclei are seen in the long bacterium. When the bacterium divides every daughter cell contains a nucleus. Besides the nucleus, the bacterium often contains several large vacuoles.
    The nucleus divides according to the type of amitosis. This type of amitosis shows some stage of the evolution to the mitosis.
    Download PDF (1346K)
  • [in Japanese]
    1954 Volume 29 Issue 5-6 Pages 228-234
    Published: 1954
    Released on J-STAGE: November 30, 2007
    JOURNAL FREE ACCESS
    Download PDF (409K)
feedback
Top