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Volume 32, Issue 2
Displaying 1-5 of 5 articles from this issue
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Torao GOTOH1957 Volume 32 Issue 2 Pages 37-47
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSTemperatures during colchicine immersion are varied from 5°C to 30°C, and the effects of temperature upon colchicine action are investigated in the Allium test. The results are as follows:
1)C-tumour formation by colchicine is prominent in high temperature condition, but low temperature suppresses it completely.
2) As the temperature becomes high, the threshold concentration for mitotic disturbance declines.
3) As the temperature becomes high, the accumulation of mitoses becomes more prominent.
4) Immediately after 48 hours' immersion, colchicine induces mitoses of a polyploid nature only in a high temperature condition. But, after the lapse of 48 hours' replacement in water, mitosis completely disappears from these roots, while in the roots treated in the rather low temperature condition (15°C) normal mitoses of newly produced tetraploid nuclei are appearing in considerable frequencies.
5) The lowest temperature condition, 5°C, induces “reductional grouping” in very high frequency.
6) In the high temperature condition, the resting nuclei are severely injured, bringing about the diminution of vitality and complete disappearance of mitosis.View full abstractDownload PDF (1946K) -
Hajime UDA1957 Volume 32 Issue 2 Pages 48-56
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe author has investigated the sex ratio at birth or the secondary sex ratio in relation to the father's age. Depending on various observations, he suggests that there is a “sexual age” in man; that sexually young men give a surplus of girls over boys and vice versa. In other words, the activity of the X- and Y-sperms or their relative ability to fertilize is influenced by the “sexual age” He affirms that this hypothesis can be applicable to horses also.View full abstractDownload PDF (917K) -
Variations induced in the Pearls' medium when transferred from the Kozi medium (1)Syuiti MORI, Sizue YANAGISHIMA1957 Volume 32 Issue 2 Pages 57-66
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESS1. Drosophila melanogaster (Oregon strain), that has long been reared by the Kozi medium (K strain), changes some characters when it is provided with the Pearl's medium (n strain). Flies, maintained on the new medium, lay more eggs per day or through their lives (averages 1.7 times) (Tables 2, 3), increase a tendency to lay eggs on the Pearl's medium (Table 5), and show an accelerated rate of development (average durations of larvae and pupae are shortened ca. 7-24 hours and ca. 5.2-9.3 hours respectively) (Tables 6, 7, 8, 9, 10).
2. When crossed, the F1 hybrids lay eggs considerably greater than the parental strains (i. e. show conspicuous heterosis) (Table 4), whereas the preference test reveals no significant difference from liking of the K strain (Table 5), and the rate of development seems to be, though slightly accelerated, nearly equal to that of the n strain.
3. We have an opinion that these changes in character are hereditary. Cautions taken in the procedures of the experiments (Fig. 1) and various results obtained seem to warrant the above opinion. As for hereditary control of these characters, both nucleus and protoplasm seem to be concerned.View full abstractDownload PDF (1053K) -
XII. The Karyotypes of Plagiothecium and Other 19 GeneraKoji YANO1957 Volume 32 Issue 2 Pages 67-72
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThirty species of mosses representing 9 families and 20 genera were studied cytologically with special reference to their karyotypes. The results obtained are given in Figures 1-31 and Table I.View full abstractDownload PDF (611K) -
Shuzo NAGAMI1957 Volume 32 Issue 2 Pages 73-74
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn 1955, a clone of Chrysanthemum rupestre MATSUMURA et KOIDZUMI was obtained from the serpentine-zone near the top of Mt. Tanigawa (1, 963m). The plant is characterized by the dwarf form as follows: (1) Heads are few and arranged in corymbs on a stem; each of these heads is about 1.5mm in diameter, without ligulate florets, but with 12-15 tubular ones (yellow). (2) The stem is about 7-9cm in length, posessing no branch at the upper part and few creepers at the lower one.
In 1956, the root-tip cells were cytologically examined by the TJIO-LEVAN's method (1950). The results are asfollows: (1) The somatic chromosome number of the plant found in the above-mentioned zone of Mt. Tanigawa is 18 (Fig. 1). (2) Apparently it is one of the Chrysanthemum-diploids.View full abstractDownload PDF (274K)
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