CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 34, Issue 2
Displaying 1-18 of 18 articles from this issue
  • I. Cytology, floral-biology and pollination mechanism
    M. L. H. Kaul
    1969 Volume 34 Issue 2 Pages 169-177
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    The paper entials a study of cytology, floral biology and pollen grain morphology of two ecological races of Mecardonia dianthera. The study has revealed that the two races exhibit similarities in chromosome number, karyotype, pollen grains, floral structure and mode of anthesis. Hence, these seem to be capable of interbreeding.
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  • II. Genetical and breeding behaviour
    M. L. H. Kaul
    1969 Volume 34 Issue 2 Pages 178-187
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Two, morphologically different forms of Mecardonia dianthera viz. erect and repent were found to be growing in nature. By breeding experiments it was found that the erect character (R) is dominant over repent character (r) and the allelic difference seems to lie at one locus. While the erect plants are either homozygous (RR) or heterozygous (Rr), the repent plants possess only the homozygous recessive alleles (rr). Since the two forms differ in ecological distribution, in habitat preference (the erect form being facultative calcicole and repent form an obligate calcifuge) and genetically, these appear to be the two edaphic ecotypes of M. dianthera. Their probable origin is also discussed.
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  • I. Pollen mother cells and pollen development
    S. Rogers
    1969 Volume 34 Issue 2 Pages 188-195
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Chromosome data place Tridax procumbens at the tetraploid level. Regularity of bivalent formation suggests that little homology exists between the constituent genomes but meiotic irregularities nevertheless occur frequently and result in some 15% of the pollen being obviously non-viable. Premeiotic aberrations in the walling of the sporogenous tissue give rise to ‘normal’ and ‘giant’ pollen mother cells. The latter are characterised by their abnormal size and often by their massive walls and elongated “tails” of either walled cytoplasm or wall material alone. The largest giant cells are binucleate.
    Meiotic irregularities in the ‘normal’ pollen mother cells include the formation of a quadrivalent or a trivalent and univalent; one or more lagging bivalents; first and second division bridges and the failure of spindle formation at either the first or second divisions. In the ‘giant’ cells delay in the onset of meiosis occurs frequently, cells showing prophase or diakinesis being found among tetrads or differentiating pollen grains. Other giant cells show highly irregular divisions culminating in a variable number of nuclei. An attempt at cleavage into microspores occurs in a minority of these cells. The nuclei in binucleate giant cells do not necessarily behave synchronously and, as in the uninucleate giant cells, often show delayed or arrested division. In the minority, where both nuclei negotiate the division successfully a “tetrad” of eight apparently normal microspores may result. While the cause of the initial irregular cytoplasmic cleavage remains unknown, it is tentatively suggested that the subsequent meiotic retardation and irregular division in the giant cells may be related to their abnormally high cytoplasmic/nuclear volume.
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  • II. Development of the embryo sac and embryo
    S. Rogers
    1969 Volume 34 Issue 2 Pages 196-201
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Obeservations of megaspore mother cell meiosis, fertilization and embryo development show Tridax procumbens to have a straightforward amphimictic type of reproduction. The embryo sac is monosporic and eight nucleate with prominent synergidae and the antipodal nuclei are contained within a short tubular haustorial outgrowth of one or three cells.
    Fertilization follows within twelve to eighteen hours of pollination and embryo development conforms to the asterad pattern. No meiotic irregularities have been seen during division of the megaspore mother cell but this does not eliminate the possibility that a proportion of the observed 15% of sterile cypselas may result from meiotic failure rather than from failure of pollination or fertilization.
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  • Ratna Sen, P. N. Bhaduri
    1969 Volume 34 Issue 2 Pages 202-212
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    In order to obtain a more definite information on the ploidy level of nodule cells, an attempt has been made to correlate the data obtained from measurements of nuclear and nucleolar volume in the cells of the nodule meristem and bacteroid region of nodules of Lathyrus sativus as compared against those of normal uninfected root meristem. By this method it has been possible to locate each cell, with their ploidy level, in the different tissues studied.
    The number of nucleoli per nucleus varied from one to four in the root meristem, one to five in the nodule meristem and one to three in the bacteroid region of nodules. The absence of the expected number of nucleoli in the 4n cells was due to the early fusion of these nucleoli during their origin in telophase.
    Disomatic cells were not observed in the root meristem either prior to or after the initiation of nodule formation. This was confirmed from measurements of nuclear and nucleolar volumes of cells. Only 2n number was counted in the root meristem but in the cells of the nodule meristem both 2n and 4n number were evident.
    A 2:1 relationship existed between the nuclear as well as nucleolar volume of cells of the bacteroid region and those of the root meristem, irrespective of the nucleolar number. In the nodule meristem, the mean nuclear and nucleolar volumes of cells were more than those of the root meristem but less than the bacteroid region.
    Infection by Rhizobium is correlated to initiation of nodule meristem. Such increased physiological activity of the cells, accelerated chromosome duplication without the corresponding cell plate formation. Hence most of the immediate cell progenies were rendered polyploid. Continued division in these cells was interrupted due to change in the relative viscosity of the cytoplasm produced by the multiplication of the invading rhizobial cells in them. For this reason the relative frequency of divisional figures with polyploid number of chromosomes in the nodules varied from plant to plant (cf. Tatuno and Kodama 1965, Kodama 1967). The nature of invasion of the rhizobia and the consequent pattern of distribution of meristem determined the relative amount of monosomatic and disomatic cells in the nodules.
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  • K. Ramachandran
    1969 Volume 34 Issue 2 Pages 213-221
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    The cytology of 27 species coming under 11 genera of the Zingiberaceae has been investigated. This includes 11 species and 2 genera not previously studied cytologically and 4 species for which the chromosome numbers determined in the present study differ from previous reports.
    The lowest chromosome number observed in South Indian plants of this family is 2n=22 and the highest 2n=96. New basic numbers observed include 25 for Boesenbergia and 21 for Hitchenia.
    The locally cultivated clone of the ginger plant (Zingiber officinale) showed evidence of structural hybridity resulting from inversions and interchanges. Zingiber macrostachyum also showed evidence of heterozygosity for inversions.
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  • Cytological features, chromosome diminution and evolution of the karyotype
    Prem P. Jauhar, A. B. Joshi
    1969 Volume 34 Issue 2 Pages 222-233
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Meiosis in 20 accessions of Panicum maximum, classifiable into 5 distinct types on the basis of morphological and epidermal features (Jauhar and Joshi 1966a, 1967), is described. Though they all had predominantly 2n=32 chromosomes, chromosome mosaicism was also encountered. Pooled data on chromosome association at diakinesis and metaphase I are presented. Out of a total of 210 cells analysed, the number of quadrivalents varied from 0-6 (mean per cell=2.04), of trivalents from 0-2 (mean=0.15), of bivalents from 4-18 (mean=11.5) and that of univalents from 0-6 (mean=0.55). On the basis of data on meiosis and on morphological features gathered earlier (Jauhar and Joshi 1966a) the nature of ploidy in this species is discussed. The most appropriate term to describe polyploidy in this species seems to be “intraspecific autopolyploid”.
    The number 2n=32 seems to have been derived through a multiplication of basic number of x=9 chromosomes followed by the elimination of 4 chromosomes during the course of evolution and differentiation of the species, rather than from a multiplication of the basic number of x=8 as suggested by earlier workers.
    Various mechanisms which may have been responsible for bringing about phylogenetic diminution of chromosome number and repatterning of karyotype are considered. The possible role of unequal translocations in bringing about chromosome reduction is discussed. It has been considered that at least 2 pairs of chromosomes could have undergone unequal reciprocal translocations followed by an elimination of 2 pairs of mutant, small chromosomes. The evolutionary implication of the occurrence of accessory chromosomes in this species is also discussed.
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  • Tomás P. Pessacq
    1969 Volume 34 Issue 2 Pages 234-240
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    A new type of amitotic nuclear division in differentiating striated muscle cells of insects (Dermatobia cyaniventris Macquart, Polybia scutellaris White, Photinus fuscus and Acromyrmex lundi) is described. It consists of a process of multiple fragmentation of a single chromatic cord, a sort of giant longitudinal macronucleus which extends almost the entire length of the immature muscle cell. We have designated this interesting nuclear structure as polykaryonema and this amitotic nuclear division process as clasmatothenesis.
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  • V. On the activity of glucose-6-phosphatase, glucose-6-phosphate dehydrogenase and malate dehydrogenase and the relationship between egg nucleolus and egg periphery
    Haruo Kobayashi
    1969 Volume 34 Issue 2 Pages 241-249
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    1. The activity of glucose-6-phosphatase, glucose-6-phosphate dehydrogenase and malate dehydrogenase in the oyster eggs and the relationship between the egg nucleolus and egg periphery were studied.
    2. It is the peripheral zone of eggs where some enzymes blocked in unfertilized eggs are released from the blockage and increases their activity remarkably after the fertilization.
    3. Upon the insemination, the egg periphery evokes the activity of the creative area and the nucleolus.
    4. Changing the direction of the first gradient axis parallel to the egg axis (the second gradient axis), KP axis regains its stability of position which has been lost by the insemination.
    5. These changes of metabolism in oyster eggs are the primary event of fertilization.
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  • Chhabi Paul, Asoke Bose
    1969 Volume 34 Issue 2 Pages 250-257
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    1. Mitotic indices in five sectors of the differentiating lens of White Leghorn chick embryo have been studied.
    2. The pattern of mitotic activity follows histogenesis of lens.
    3. The regression of mitotic activity of lens cells has a quadratic trend.
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  • Sally Kelly, Rydia Almy
    1969 Volume 34 Issue 2 Pages 258-261
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    A mixture of paired and unpaired chromosomes was the predominant configuration of homologues in air-dried suspensions of polyploid metaphases from both amnion and leukocyte cultures. The relatively normal frequency distributions of the homologue pairings were interpreted as evidence for a continuous population of polyploids in cultured tissues, from diplochromosomes through variable degrees of pairing to “randomly positioned” chromosomes.
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  • M. C. Risueño, G. Giménez-Martín, J. F. Ló ...
    1969 Volume 34 Issue 2 Pages 262-272
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    1. The prophases of meioses in a particular pollen-sac of the monocotyledons Scilla non-scripta and Allium cepa run a synchronized course and their protoplasts are joined together by connexions.
    2. The connexions are of different dimensions and they may be of either cytoplasmic or nuclear character, or they may arise from bridges set up by cell organules.
    3. The connexions have been observed throughout the prophase of meiosis only. Their possible origin and the consequences are discussed.
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  • V. Mitosis
    Yoshinari Kuwada
    1969 Volume 34 Issue 2 Pages 273-277
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
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  • Premeicotic division and meiosis
    Yoshinari Kuwada
    1969 Volume 34 Issue 2 Pages 278-292
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
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  • Shu-Ting Chang, Sze-Shuen Chu
    1969 Volume 34 Issue 2 Pages 293-299
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Modified cytological techniques were used in this study of the nuclear phenomenon in the basidium of V. volvacea. The number of nuclei in the cells of vegetative mycelia varried from 2-36. The short cells of subhymonium layer had a reduced number of 2-4. The two haploid nuclei were found both in the supporting cells and in the young basidia. Conventional meiotic figures were observed. There were nine bivalent chromosomes at early metaphase aligning themselves in a semi-circle at the upper part of basidium. Resting compact nuclei were at intervals of karyogamy and first meiotic divisions. Neither spindle nor centrioles were observed with this preparation. Migration of the four postkaryotic nuclei into the spores is by slipping of nuclear material through the narrow sterigma. Preliminary suggestion directs to the point that this fungus is homothallic. The sexual mechanism and the alignment of second meiotic spindle in relation to its incompatibility factors is still poorly understood.
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  • I. The haemocytes of Epicauta cinerea (Forster), and a synonymy of haemocyte terminologies
    A. P. Gupta
    1969 Volume 34 Issue 2 Pages 300-344
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Epicauta cinerea possesses plasmatocytes, granular haemocytes, spherule cells, oenocytoids, and cystocytes. Adipohemocytes, podocytes and vermiform cells are absent in the blood of this beetle.
    Haemocyte terminologies have been synonymized, using several classifications by various authors. This study revealed that haemocytes have not yet been studied in Protura, Diplura, Collembola, Isoptera, Embioptera, Zoraptera, Phthiraptera, Corrodontia, Thysanoptera, Raphidoidea, Megaloptera, Neuroptera, Mecoptera, and Siphonaptera. In terms of number of species studied, Orthoptera and Coleoptera are the most extensively studied groups, while Dermaptera, Plecoptera, Trichoptera and Thysanura are the most poorly studied orders. Of all the orders, only Orthoptera, Coleoptera, Lepidoptera, and Diptera, have all the 7 or 8 types of haemocytes.
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  • A. V. LeBouton
    1969 Volume 34 Issue 2 Pages 345-350
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
    Soluble liver cell proteins were studied from two approaches: 1) electrophoretic mobility and 2) kinetics of specific radioactivity after injection of tritiated leucine into rats. The electrophoretic fractions were classified according to mobility, magnitude of highest specific radioactivity and how long after injection of the radioisotope the peak specific radioactivity occurred. These measurements were discussed in relation to the degree of heterogeniety of the electrophoretic fractions. Conclusions were that faster migrating fractions are less heterogeneous than those with slower mobilities, and with respect to the faster anodally migrating fractions, that they are probably intracellular proteins with a rapid metabolism or they represent sub-units of proteins.
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  • Ishwari Prasad, David Pramer
    1969 Volume 34 Issue 2 Pages 351-352
    Published: June 25, 1969
    Released on J-STAGE: March 19, 2009
    JOURNAL FREE ACCESS
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