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Volume 16, Issue 1
Displaying 1-6 of 6 articles from this issue
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Atusi Yamaura1940 Volume 16 Issue 1 Pages 1-9
Published: 1940
Released on J-STAGE: April 04, 2007
JOURNAL FREE ACCESS1. On the shapes of the eye-lid(I), in the peculiarities in infolding the fingers of both hands(II), in the head hair-whorl types(III) and in the inward flexibility of the first joint of the thumb(IV) the writer investigated the frequencies of each character in genuine Japanese and in Coreans (the latter on I and II).
2. In four cases the double eye-lid(I), the right fingers upper infolding(II), the dextral head hair-whorl(III) are recognizable as probable simple Mendelian dominants over allelomorphs and the flexibility of the first joint of the thumb(IV) as a recessive.View full abstractDownload PDF (578K) -
Taku KOMAI, Takesi TAKAKU1940 Volume 16 Issue 1 Pages 10-13
Published: 1940
Released on J-STAGE: April 04, 2007
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Toshio AKEMINE1940 Volume 16 Issue 1 Pages 13-16
Published: 1940
Released on J-STAGE: April 04, 2007
JOURNAL FREE ACCESSIn a clone of Hosta undulata Bailey (2n=60, Text-fig. 1) extremely aberrant meiosis was observed. All PMCs observed showed abnormal configurations especially of larger chromosomes at diakinesis and MI, such as, univalents (Text-figs. 4-19), fragments (Text-figs. 7-19), translocated segments (Text-figs. 10-13), terminally associated bivalents (Text-figs. 7, 8 and 16) and polyvalents (Text-figs. 12-14), the last being interpreted as the results of reciprocal translocation. These abnormalities lead to the aberrations of chromosome behaviour in the farther stages, such as, occurrence of lagging chromosomes, fragments, chromatin bridges etc. (Text-figs. 20-26). These aberrant karyokineses, however, arc followed by normal cytokineses, no microcyte being formed at the tetrad stage. The pollen grains are almost completely sterile and no seed is produced. These abnormal chromosome configurations observed are ascribed to certain structural changes occurred at the early stage of meiotic prophase, which are supposed to be genetically controlled. The author is indebted to Professor H. Matsuura under whose guidance and criticism this work has been carried on.View full abstractDownload PDF (422K) -
Hajime MATSUURA1940 Volume 16 Issue 1 Pages 17-18
Published: 1940
Released on J-STAGE: April 04, 2007
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Senji TAKIZAWA1940 Volume 16 Issue 1 Pages 18-22
Published: 1940
Released on J-STAGE: April 04, 2007
JOURNAL FREE ACCESSIn nine species of the genus Acer, the chromosome numbers were counted in either root-tip cells or PMCs. All the species examined were diploid (n=13, 2n=26) (Tab. 1). In Acer polyploid species, however, are reported by previous workers only in two systematical sections (RUBRA and SPICATA), and not in others.
Meiosis in PMCs was regular in the five species examined excepting one plant of A. japonicum. The secondary pairing of bivalents was obviously shown in all these species. Especially a statistical study was made on the frequency of various pairing types at polar view of MI in 188 PMCs of A. ornatum var. Matsumurae (Tab. 2). The maximum pairing type consists of three of three paired bivalents and two of two paired bivalents, indicating five groups of chromosomes. Consequently it seems to be able to assume that the haploid chromosome number in the genus Acer, 13, is that secondarily derived from an original basic number of five. This assumption seems to be interesting in relation to the fact that the basic number of the genus Aesculus which is related closely to the genus Acer, is 10 (possibly 5 as inferred from the secondary pairing), and to the observation of Meurman that the somatic chromosome complement of A. platanoides is able to be classified into the five chromosome types.
In one plant among three examined of A. japonicum var. typicum, several univalents ranging from two to six, and chromosome fragments were usually observed. In most cases the univalents divide at MI after the regular separation of bivalents took place. Rarely the chromatin bridges were observed at both the first and second anaphases, and furthermore cells at the second anaphase showing octad formation were met with. Probably such abnormal divisions will be found in other Acer species, as this genus is so polymorphic that we can expect such chromosome aberrations as usually found in other cultivated plants.View full abstractDownload PDF (408K) -
TUTOMU HAGA1940 Volume 16 Issue 1 Pages 23-35
Published: 1940
Released on J-STAGE: April 04, 2007
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