CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 35 , Issue 2
Showing 1-16 articles out of 16 articles from the selected issue
  • Yoshiwo Katayama, Shojiro Shida
    1970 Volume 35 Issue 2 Pages 171-180
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The authors worked previously on the relative contents of chlorophylls by means of paper chromatography. Further the changes of chlorophyll a and b contents as well as the ratio a/b were studied by electrospectrophotometer on different materials under various environments.
    1. The change of chlorophyll contents was not found generally among the individuals of the same strain in sweet potato and rice. This result is considered to be due to the high homozygositic characters in these strains or lines.
    2. The change of chlorophyll contents was observed corresponding to the developmental stages of leaves in sweet potato. In the growth of ordinally cultivated plants, the chlorophyll contents reached the maximum in some stages (the 7th8th leaves from the top of the stem), and then decreased (toward the stem basis). However, the contents of chlorophyll a and b were considered to change in parallel causing no difference in the ratio a/b.
    3. The differences of the chlorophyll contents due to the strains and lines were small in sweet potato but large in those of rice; the content differences in the latter case seem to be attributed to the degree of differentiations in the strains or lines.
    4. Concerning the differences of the influence by various fertilizers on the test plants (sweet potato and rice), nitrogen and potassium seem to be considerably favorable to increase the chlorophyll a and b contents. Especially the nitrogen-rich fertilizer increased the chlorophyll contents and the nitrogenless one decreased them. However, the ratio a/b in the both test plants was scarcely affected by these fertilizers.
    5. The influence of environmental factors on the sweet potato brought different values on the chlorophyll a and b contents and on the ratio a/b. Especially the influences on the chlorophyll contents were remarkable at the test plants in dry moisture plot or in the fill water plot.
    6. The effect of chemicals on the chlorophyll contents was tested on Lagenaria. Growth promoting substances seem to increase the chlorophyll contents, but weed killers seem to decrease the contents.
    7. The change of chlorophyll contents comprises the change of absolute amount and the increase or decrease of chlorophyll a or b content. The relationship between the chlorophyll contents and the photosynthesis should be elucidated in future researches.
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  • R. P. Chandola, S. N. Jain
    1970 Volume 35 Issue 2 Pages 181-196
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. A detailed study of cytology of 36 varieties of Pennisetum typhoides L. has been carried out.
    2. These varieties representing far stretched parts of the globe exhibit remarkable differences in their size and gross morphology. The different varieties differ in the number of different type of chromosomes in regard to structure alterations and size differences. These factors are constant for the variety and may be used as its cytological label.
    3. Chromosome type No. 26 exists in all the varieties except in variety Nos. 4, 8 and 33 where it is presumed to have undergone certain structural modifications during the course of evolution of these varieties.
    4. By study of evolutionary trends on the basis of chromosome symmetry, size etc. it is inferred that only the eight types out of 36 studied are the old ones.
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  • A. K. Koul, R. N. Gohil
    1970 Volume 35 Issue 2 Pages 197-202
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    All collections of Allium sativum Linn. included in the present study were viviparous on account of the replacement of flowers by bulblets. Breakdown of sexual reproduction in the species is caused by the failure of microspores to differentiate into pollen grains. This is attributed to the appearance of bulblets on the inflorescence which rob the developing flowers of all nutrition.
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  • K. P. S. Sisodia
    1970 Volume 35 Issue 2 Pages 203-212
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. Chromosome number of Thelepogon elegans, a monotypic genus, has been found to be 2n=10. This is the first record of chromosome number in this monotypic genus. It forms five bivalents at metaphase I. The grass is diploid. Pollen viability is 98%.
    2. In few P.M.Cs ten bivalents instead of five have been observed at diakinesis and metaphase I. This is a case of syndiploidy.
    3. In one plant of this grass, spontaneously occurring associations of chain of four, six or an open ring of eight chromosomes have been observed showing interchange heterozygosity. Pollen viability is 97%.
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  • Asit B. Mukherjee, Don M. Rees
    1970 Volume 35 Issue 2 Pages 213-219
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The chromosome morphology and behavior pattern during spermatogenesis in Aedes dorsalis was studied. The results were compared with the findings of similar investigations in other species of mosquitoes. Chromosome preparations were made from testes-tissue of fourth instar and pupal stages by the squash technique and stained with aceto-lactic-orcein. The two testes of an individual may have cells at different divisional stages. Leptotene and zygotene stages of meiotic prophase were not distinguishable. The unwinding of the homologous chromosomes in later stages of prophase I was found to progress at different rates on either side of the centromere. The separation of the chromosomes during anaphase I was mostly synchronous. The polarization of arms of the prophase II chromosomes was observed. The repulsive forces between the sister chromatids in metaphase II were less apparent and the chromosomes at this period were H-shaped in configuration.
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  • Seizi Tatuno, Ryuso Tanaka, Masanori Masubuchi
    1970 Volume 35 Issue 2 Pages 220-226
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    In the present investigation DNA synthesis of X-chromosome of Pellia neesiana (n=9), Hepaticae, was studied by the use of the H3-thymidine autoradiography.
    1. DNA in the heterochromatin of X-chromosome of female Pellia neesiana was found to replicate during the early and the middle stages of DNA synthetic phase.
    2. DNA in the euchromatin of both X-chromosome and autosomes was found to replicate continuously from the early to the last stages of DNA synthetic phase.
    3. DNA in the heterochromatin of X-chromosome was found to replicate mainly in the diffused state of heterochromatin during the early stage of DNA synthetic phase.
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  • V. R. Dnyansagar, I. V. Sudhakaran
    1970 Volume 35 Issue 2 Pages 227-241
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Tetraploidy was induced in Vinca rosea Linn. by treating seeds with. 0.4%/ of aqueous colchinine. By selfing the C1 plants, C2 progeny was raised. The tetraploid is characterised by possessing a stout stem and branches, broader and shorter leaves, larger stomata, slower rate of growth, larger pollen grains and high pollen sterility. The total alkaloid content is more in both generations of the tetraploid plants. Mitosis in the tetraploid is almost normal. Meiosis in both Cl and Cz plants is irregular. It is analysed statistically. The presence of univalents, micronuclei of different shape, spindle abnormalities followed by aggregation of chromosomes into groups at metaphase, and anaphase, irregular anaphase and formation of polyads have been frequently observed in the PMC's.
    The coefficient of correlation between the abnormalities at different stages of meiosis and pollen sterility has been determined. There is no significant correlation between these irregularities and pollen sterility.
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  • P. J. Kaltsikes, L. E. Evans, E. N. Larter
    1970 Volume 35 Issue 2 Pages 242-251
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Chromosome segregation was studied in pentaploid hybrids resulting from crosses between extracted AABB tetraploids and varieties of common wheat. Varietal differences were observed in univalent elimination in the F2 progeny. No clear-cut association could be made between the differences in cytological behaviour that were observed in the various meiotic stages examined and the final outcome in terms of mean chromosome numbers in the progeny.
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  • Walter Nagl
    1970 Volume 35 Issue 2 Pages 252-258
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The course of the cell cycles during the early development of the suspensor in Phaseolus coccineus and Ph. vulgaris is a factor influencing the occurrence of polytene chromosomes within the mature, highly endopolyploid nuclei. If there is a continuous sequence of endomitotic cycles, giant chromosomes arise. If the early endopolyploidization is interrupted by a polyploid (4x, 8x, or 16x) mitosis, the nuclear structure remains diffuse, also during the subsequent endomitotic growth of the nuclei.
    A scheme is given to demonstrate that a specific short-cut of the cell cycle is necessary for the origin of polytene chromosomes in general.
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  • L. D. Vijendra Das
    1970 Volume 35 Issue 2 Pages 259-261
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • M. Clara Mallmann, F. P. Pinheiro, F. M. Salzano, M. Ayres
    1970 Volume 35 Issue 2 Pages 262-270
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Two sublines of H. Ep. 2, obtained from New Haven (NH) and São Paulo (SP) respectively, were studied in relation to their morphology, growth rate, virus susceptibility and chromosomes. The São Paulo subline was divided into two, one cultivated in Hanks lactalbumin medium plus 20% of calf serum and the other in modified Eagle's medium, to investigate the possible influence of the medium of cultivation on these variables. This influence proved to be small. But significant differences were observed between the two sublines, H. Ep. 2 NH showing a lowered rate of growth, less susceptibility to virus infections and a higher modal chromosome number. The changes in chromosome number were of such a nature that there was practically no overlapping in the range of variation in the two sublines. Groups B, D and F were the most affected.
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  • Tsuneyoshi Kuroiwa, Nobunori Tanaka
    1970 Volume 35 Issue 2 Pages 271-279
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Asynchronous replication of chromosomal DNA was demonstrated in root tip cells of Crepis capillaris by means of pulse labelling with tritiated thymidine and autoradiography. The results obtained may indicate that DNA replication starts almost synchronously in all chromosomes but terminates asynchronously. The replication term of the chromosome 3 is shorter than that of others. Time of initiation and termination of DNA replication differ in bulk as well as in certain regions. This trend is also true even in a single chromosome.
    As for sequential incorporation of 3H-thymidine, two distinct labelling patterns were noticed. Namely, in chromosomes 1 and 2, early replication was observed in subterminal regions, while late replication occurred in regions, both sides of the centromere and in the interstitial region of the long arm. These results may strongly suggest that the replication of chromosomal DNA does not proceed uniformely in longitudinal direction, either distally or proximally, along the chromosome arms. Further investigations were undertaken to make clear the relationships between DNA replication patterns and the chromosome structure. In cytologically, there were two types of DNA in the chromosomes, the one is the late replicating and heterochromatic and the other, the early replicanting one, euchromatic.
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  • Naomichi Inui, Shozo Takayama
    1970 Volume 35 Issue 2 Pages 280-293
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Microspectrophotometric evaluation of the DNA content of cell nuclei and 3H-thymidine autoradiography were carried out on the cells from cerebellums, thymus, glandular stomach, liver, and kidney of embryonic, suckling, and adult Syrian hamsters and Buffalo rats. The results obtained from this study were as follows: 1) In both hamsters and rats, the cells with diploidDNA (2C) showed the main modal peak in various organs examined of embryonic to 6-month-old animals. 2) In liver tissues, tetraploid cells (4C) began to appear in the 3-day-old animals and increased gradually in number until 6 months old, 40% or more of the cells showing tetraploid value of DNA. 3) No cells with intermediate or extra DNA were found in tissues examined during the growth period of animals, and neither octaploid nor higher nuclei appeared even in liver tissues of the adults. 4) 3H-thymidine labeling index showed high percentages in organs of embryo to 1 day after birth. 5) 3H-thymidine labeling index rapidly declined 1 week after birth in all the organs except in the cells of glandular stomach. 6) There is a close correlation between labeling and mitotic indices and the distribution pattern of DNA value. From these data it would be supposed that the appearance of the cells with extra or intermediate DNA value is due to the existence of the cell in S-phase.
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  • LeRoy C. Saylor, Holly A. Simons
    1970 Volume 35 Issue 2 Pages 294-303
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • III. The genomic constitution of O. punctata and O. eichingeri
    Chao-Hwa Hu
    1970 Volume 35 Issue 2 Pages 304-318
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The wild African rice taxa Oryza punctata and O. eichingeri, which are similar in many morphological characters, were often incorrectly identified and used in genome analysis studies. A total of ten strains of O. punctata, two strains of O. eichingeri and two intermediates of the punctata-eichingeri complex were observed and six strains used as parents to produce species hybrids. Seventeen cross combinations were succeeded to make F1 hybrids. It was found that both species have diploid and tetraploid forms and they could be distinguished by certain morphological characters. The genomes of diploid and tetraploid forms of O. eichingeri were similar to those of O. officinalis and O. minuta, CC and BBCC. In the crosses involving diploid punctata, however, various pairing pattern were found in different hybrids. Strain W1514 produced a maximum of eight bivalents with genome A of O. sativa, while anothers strain 101434 showed seven bivalents with both sativa and diploid eichingeri. These two strains gave 12 bivalents in the F1 hybrids with O. minuta and tetraploid eichingeri. Further, in the triploid hybrids of sativa×punctata (W1023) and latifolia×punctata (101434) five to six bivalents were found. The data suggest that the genome of diploid punctata is homoelogous to both genomes A and C.
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  • H. Merchant
    1970 Volume 35 Issue 2 Pages 319-334
    Published: June 25, 1970
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    An electron microscope study of the process of segmentation in the rabbit ova is described. During the first division cytoplasmic extrusions were observed, the contents of which appeared to pass into the perivitelline space. Vitelline inclusions were noted, as well as mitochondria with cristae which were positioned in an unusual manner. A well developed Golgi complex and several multivesicular bodies were also seen. During early cleavage annulate lamellae were observed inside the nucleus. The nucleolus changed from a dense homogeneous globular structure to a heterogeneous reticular structure. This change coincided with the appearance of large numbers of cytoplasmic polysomes. At the morula stage differences were noted in the density of the fundamental matrix between the various blastomeres. The significance of these developmental changes is discussed.
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