CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 2, Issue 2
Displaying 1-3 of 3 articles from this issue
  • CONWAY ZIRKLE
    1931 Volume 2 Issue 2 Pages 85-105
    Published: March 16, 1931
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    1. The root tip and cambium of Pinus Strobus were fixed in several different fluids so as to preserve the chromatin, plastin, and mitochondria in the following combinations:-(1) chromatin, plastin, and mitochondria fixed; (2) plastin and mitochondria fixed and chromatin dissolved; (3) chromatin and plastin fixed, mitochondria dissolved; (4) plastin fixed, mitochondria dissolved, chromatin rendered unstainable; (5) chromatin fixed, mitochondria dissolved, plastin ren-dered unstainable. It was thus possible to separate the plastin from the chromatin, chemically, and to follow it through the several mitotic phases unobscured by any other nuclear constituent. It was also possible to distinguish any possible granules of plastin in the cytoplasm from the mitochondria.
    2. The organization of nucleolar material in both the resting and dividing nucleus of Pinus differs in many important details from that recently described in a number of angiosperms. The resting nucleus of Pinus contains an average of six nucleoli which are in intimate contact with the chromatin threads of the reticulum. On the initiation of karyokinesis, each nucleolus becomes attached to the spireme. The plastin passes into the spireme and is distributed to the daughter cells as a part of the chromosomes. On the reorganization of the daughter nuclei, the plastin is consolidated into the typical nucleoli of the resting cell. Unlike Zea, the Pinus nucleoli do not persist to metaphase, and diserete globules of plastin do not, pass from the equatorial plane to the poles of the spindle. No evidence was found of any fragments of nucleolar material passing out into the cytoplasm.
    3. Two distinct substances can be observed in the resting nucleoli in living cells. As these substances have a different index of refrac-tion, the nucleoli appear vacuolate. These substances can be separated by fixation in the resting nucleus and in the later telophases. During the other mitotic phases, however, they have not been separated, so that, at present, it is not possible to trace each one individually through the entire cycle of cell division. Neither substance is chromatin.
    4. The bearing of the activity of plastin during mitosis upon several theories concerning the forces involved in cell division is dis-cussed.
    The author wishes to express his obligation to Professor I. W. BAILEY for his assistance throughout the course of this investigation and especially for his help in preparing the cambium for cytological investigation. Professor BAILEY's preparation of living cambial tissue made it possible to check the several fixation images wich the struc-tures of untreated cells. The author also wishes to thank Miss ANNA F. FAULL for drawings in Plate 6 and the Text-Figure.
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  • II. Aegilotricum und Aegilops cylindrica
    H. KIHARA
    1931 Volume 2 Issue 2 Pages 106-156_3
    Published: March 16, 1931
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
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  • HIROSHI YAZAWA
    1931 Volume 2 Issue 2 Pages 157-173
    Published: March 16, 1931
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    1. In Makinoa crispata blepharoplast (or centrosome) was found neither in the earlier divisions of spermatogenous cells in the antheridium, nor at each spindle pole in the division of the spermatid mother-cell.
    2. Blepharoplast seems to arise de novo in the cytoplasm of the spermatid.
    3. In a certain stage of development of the spermatid, there is observed a differentiation of the cytoplasm into inner and outer portions, the inner portion forming a bell-shaped connection between the blepharoplast and nucleus.
    4. The partition wall between the two spermatids formed from one mother-cell is persistent throughout.
    5. In Marchantia polymorpha blepharoplast (or centrosome) is clearly observed at each spindle pole in the division of the spermatid mother-cells. [Cf. foot-note an p. 167.]
    In concluding I wish to express my hearty thanks to Prof. Fuju, under whose guidance this study was made, for his kind advice and criticism. My thanks are also due to many other gentlemen for their kind help in various ways.
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