CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 36 , Issue 2
Showing 1-22 articles out of 22 articles from the selected issue
  • M. M. Sampaio, R. M. Barros, M. Ayres, O. R. Cunha
    1971 Volume 36 Issue 2 Pages 199-204
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The two morphologically distinct species G. carbonaria and G. denticulata have 52 chromosomes. The same number found in Clemmys japonica and Geoclemys reevesii. This number is, however, about double that of the number described in species of genus Podocnemis of the Amazon Region of Brazil. The two species show marked morphological similarities in their chromosomes but the 12th pair is dissimilar, being metacentric in G. carbonaria and acrocentric in G. denticulata.
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  • Benny M. Varghese
    1971 Volume 36 Issue 2 Pages 205-209
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The cytology of male and female plants of Trichosanthes palmata Roxb. has been studied. Both plants showed 22 chromosomes in root tip cells. Meiotic studies on the male plants revealed the presence of 11 bivalents in pollen mother cells. These plants are believed to be diploids on the basic number x=11. The present finding of a diploid and earlier report of a tetraploid reveal the existence of intra specific polyploidy in T. palmata. Critical examination of karyotypes in the male and female plants did not reveal the presence of morphologically distinct sex chromosomes associated with the dioecious habit.
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  • James R. Estes
    1971 Volume 36 Issue 2 Pages 210-218
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Meiosis in Artemisia douglasiana (Satus Creek 11I) is achiasmatic, resulting in the production of univalents at metaphase I. Restitution nuclei are a major effect of this desynapsis, and the gametes were found to have the unreduced or close to the unreduced chromosome number. The chromosome numbers of open-pollinated progeny formed an aneuploid series intermediate between the parental chromosome level (2n=4x=36) and the hexaploid level (2n=6x=54). However, one of the off-spring from an interspecific cross proved to be eupolyploid.
    Desynapsis is proposed as one possible mechanism for the production of natural polyploids.
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  • III. Gametocide-induced male-sterile Vicia faba L
    C. L. Kaul
    1971 Volume 36 Issue 2 Pages 219-228
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Meiosis in 2, 2-dichloropropionic acid-induced male-sterile plants of Vicia faba L. has been studied. Meiosis was regular in nearly 70 per cent of total pollen mother cells studied. The remaining cells were characterized by varying degrees of stickiness, which resulted in multiple chromosome associations and in extreme cases clumping of entire complement at prophase and metaphase I. Disjunction of chromosomes in such cells was characterized by bridges and laggards. Bridges some times persisted upto sporad stage. Multipolar spindles were observed at both the divisions of meiosis. In some cells, a wall was laid soon after the completion of first nuclear division, thereby resulting in the formation of dyads. Dyads did not undergo a second division.
    All these abnormalities resulted in the formation of 30 per cent polyads with 2-10 microspores. Some of the pollen mother cells at various stages of division, exhibited the phenomenon of “cytomixis”.
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  • K. Sree Ramulu
    1971 Volume 36 Issue 2 Pages 229-236
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytological observations were made in M1 plants treated with radiations (X- and gamma rays), chemical mutagens (EMS, MMS, DES and NEU) and their combination treatments to study the effects on types of chromosome associations, the frequency and type of other nuclear and nucleolar anomalies in three cultivated varieties (Co. 11, Co. 12 and Co. 18) of Eu-Sorghum. Reciprocal translocations having ring or rod configuration occurred in higher frequency than the other types of structural changes. A positive correlation between the percentage of M1 plants crarying chromosomes with interchanges and the dose of mutagens was observed. The treatments with radiations induced not only a greater frequency of interchanges per cell but also a higher percentage of PMCs with quadrivalents than treatments with chemical mutagens. The effect on disturbances in meiosis as judged by the chromosome association was measured by the mean number of univalents, bivalents and multivalents per cell. The combined treatments did not lead to any additive effect in inducing chromosome breakages. Meiotic anomalies other than translocations comprised mostly laggards, bridges tripolar spindles, micronuclei and multi-nucleoli. The percentage of PMCs with meiotic disturbances was on the increase with increase in dose of the mutagens. Radiation treatments induced the maximum frequency of PMCs carrying meiotic anomalies as compared to treatments with chemical mutagens.
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  • Arun Kumar Sharma, Ira Ghosh
    1971 Volume 36 Issue 2 Pages 237-247
    Published: June 25, 1971
    Released: March 19, 2009
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    Detailed karyotype studies have been carried out on 15 different species and varieties belonging to 7 genera of Bromeliaceae, viz. Ananas, Bilbergia, Caraguata, Cryptanthus, Dyckia, Neoregelia and Pitcairnia.
    Although gross homogeneity in the karyotype among the members of the 7 genera is noticed, yet a critical analysis shows that each species and variety is characterised by the distinctive karyotype of its own, particularly in nature of secondary constriction-so structural alteration of chromosomes has been the prime factor in evolution within the family.
    Out of the 4 tribes within this family, in Tillandsieae, the prevalent chromosome series is 8 or 16; in Bromelieae it is 9, 18 and 25 and in Pitcairnieae it is 25. It has been suggested that 8 represents the basic set for this family from which other numbers might have been derived. On the basis of past report and present investigations a rearrangement of different tribes is suggested-Tillandsieae with its basic set of 8 should represent primitive whereas Pitcairnieae with a series of 25 forms the present climax of evolution. The intermediate stages are possibly represented by Bromelieae some of which are common to Tillandsieae and others with Pitcairnieae.
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  • R. K. Jayaprakash, B. R. Murty
    1971 Volume 36 Issue 2 Pages 248-252
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Meiotic behaviour of a phenotypic instability of flower reversion is examined in N. rustica to relate it to its abnormal segregation in its progenies for this character. Several irregularities like non-synchronised meiosis, multivalents and stickiness of chromosomes were observed in all cells in varying degrees. The differences in degrees of meiotic irregularities could be related to the heterogeneity of segregation. The causes for the aberrant cytological behaviour could be traced to the metabolic blocks in the revertant for glycine and three more amino acids.
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  • A. K. Koul, R. N. Gohil
    1971 Volume 36 Issue 2 Pages 253-261
    Published: June 25, 1971
    Released: March 19, 2009
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    Triploid A. cepa var. viviparum has been earlier described as a genomic allotriploid with the genomic formula AAB. Studies conducted on the mode of chromosome pairing and used in conjecture with the nature of karyotype, however, favour segmental allotriploid status for the taxon with the genomic formula A A' A''. A. fistulosum and A. cepa are regarded as the progenitors of ‘Pran’ (3X A. cepa var. viviparum). The unreduced pollen grains of the F1 hybrid through backcrossing seem to have resulted in the formation of the triploid cultivar. Like many other polyploids, the latter has taken to vegetative mechanism of propagation to overcome the bottleneck of sterility.
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  • III. Life-cycle of Schizosaccharomyces pombe
    Akira Yuasa, Masako Osumi, Emiko Masuzawa
    1971 Volume 36 Issue 2 Pages 262-268
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. The life-cycle of Schizosaccharomyces pombe is thought as follows: vegetative cells-conjugation of the cells-nuclear fusion-meiosis-formation of four ascospores-germination-vegetative cells.
    2. Two chromosomes appear in mitosis of vegetative cell.
    3. The spindle is formed intranuclearly. The cell plate is formed by the function of both phragmoplast and annular thickening.
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  • W. Gottschalk, O. Konvicka
    1971 Volume 36 Issue 2 Pages 269-280
    Published: June 25, 1971
    Released: March 19, 2009
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    Die Meiosis einer Mutante von Brassica oleracea var. capitata wurde analysiert. Hierbei wurden folgende Befunde erhalten:
    1. In der 1. Metaphase treten 0-12 Univalente je PMZ auf; der Mit-telwert lag bei 3, 8. Da im Pachytän normale Paarung aller Homologen zustande kommt, kann die Univalentenbildung nur auf einer Herabsetzung der Chiasmenfrequenz beruhen; die Mutante gehört folglich zur Gruppe der desynaptischen Formen.
    2. Einige der Univalente werden unmittelbar in die Tochterkerne der 1. Interphase einbezogen. Die übrigen werden nachträglich noch in die Aquatorialplatte eingeordnet, ihre Chromatiden wandern an die Pole. Die beiden Tochterkerne setzen sich folglich aus Chromosomen und Chromatiden in unterschiedlichen Zahlenverhältnissen zusammen. Die für alle übrigen desynaptischen Mutanten anderer Species charakteristische Bildung zahlreicher Mikronuklei wird durch diesen Mechanismus vermieden. Als Folge hiervon liegt die Störungsrate auch in den späteren Stadien der Meiosis niedriger und es wird ein relativ hoher Anteil funktionsfähiger Pollen produziert; er lag bei etwa 30%.
    3. In Testkreuzungen konnte die Funktionsfähigkeit dieser Pollen bestätigt werden, während die Mutante eine äußerst geringe Anzahl funktionsfähiger Eizellen bildet. Es kann angenommen werden, daß sich das mutierte Gen stärker auf die Makrosporogenese auswirkt als auf die Mikrosporogenese.
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  • Berwind P. Kaufmann, Helen Gay
    1971 Volume 36 Issue 2 Pages 281-284
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    An intercalary locked-loop configuration, produced in salivary-gland chromosome 2R of Drosophila melanogaster, suggests that patterns of somatic pairing and of non-homologous association are established at about the same time in the course of development. Assumedly this is not later than the early second-instar larval stage. A high degree of polyteny is subsequently attained while the chromosome is locked in a tight loop configuration.
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  • Radharanjan Hazra, Archana Sharma
    1971 Volume 36 Issue 2 Pages 285-297
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Detailed cytological studies have been carried out on nine species and varieties under the genus Sida. Some varieties of S. rhombifolia showed the presence of accessory chromosomes and so populations of these varieties from different ecological habitats were collected. Paradichlorobenzene and aesculin were found to be the most effective pretreating chemicals in studying their somatic chromosomes. The chromosome numbers reveal that polyploidy, both inter- and intraspecific, has played a role in evolution in the genus, in addition to aneuploidy. Of the different basic numbers (n=7, 8, 9) 7 is found to be deep seated.
    In addition to polyploidy, structural rearrangements of chromosomes have been observed in all cases showing their prominent role in speciation within this genus. Moreover, regular bivalent formation even in intraspecific tetraploids suggests structural changes during evolution. However homogeneity of the genus as a whole is indicated in the general pattern of the karyotypes of different species and varieties and also in the similarity in their total chromatin length. Within this genus at least polyploidy in speciation has not been associated with diminution in chromosome size.
    The constant presence of accessory chromosomes in a phenotypically distinct population of S. rhombifolia, indicates some selective advantage. Regarding the origin of accessory chromosomes, it has been suggested that some of the extra chromosomes of high polyploid cells which are often found in the individuals bearing accessories, may lose their function and undergo heterochromatinization and as such are transformed into accessory, ones.
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  • Ronald Matte, Motomichi Sasaki
    1971 Volume 36 Issue 2 Pages 298-303
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    A method of culture of human male germ-cells is described. Autoradiographic evidence of germ-cell differentiation in vitro till the early spermatid stage is presented.
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  • II. Mentha arvensis Linn.×M. longifolia (Linn.) Huds
    S. N. Sobti
    1971 Volume 36 Issue 2 Pages 304-308
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    F1 hybrid between M. arvensis sub. sp. haplocalyx Briq. var. piperascens Holmes and M. longifolia (Linn.) Huds. was produced. The hybrid is inter-mediate in morphological characters between the two parents and is completely sterile. The detailed cytology of the hybrid and the parents is described. The genome present in M. longifolia has no homology with any of the genomes present in M. arvensis sub. sp. haplocalyx var. piperascens.
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  • K. L. Mehra, P. R. Sreenath, S. A. Faruqi
    1971 Volume 36 Issue 2 Pages 309-320
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Chromosome associations during metaphase I of meiosis were analysed in Setcreasea pallida, S. brevifolia, S. ovata, S. purpurea and interspecific hybrids, back-crosses and F2 populations between these species. Multivalents were observed besides bivalents in the tetraploid S. brevifolia, S. ovata, S. purpurea and interspecific hybrids, backcrosses and F2 populations between these species. The frequencies of cells with 0, 1, 2 ... 6 multivalents were tested against the expected binomial in triploid and tetraploid species and hybrids.
    Each of the six sets of four chromosomes in Setcreasea brevifolia var. brevifolia, S. purpurea and S. ovata were capable of pairing as a quadrivalent. The distribution of multivalents was binomial. Autopolyploid origin of these species was proposed.
    In most of the interspecific hybrids between the abovesaid species, the distribution of multivalents was binomial. It was proposed that the differentiation between the species of Setcreasea is due mainly to gene mutations rather than due to changes in chromosome structure.
    A genetic mechanism causing chromosomes to pair mostly as bivalents was proposed. The cytogenetic significance of predominant bivalent formation was discussed.
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  • VI. Evolutionary role of numerical alteration in chromosomes in varietal differentiation in Plumeria
    S. S. Raghuvanshi, A. K. S. Chauhan
    1971 Volume 36 Issue 2 Pages 321-331
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytology of Plumeria rubra acutifolia (2 vars.) and Plumeria alba (2 vars.) was studied. The two varieties of Plumeria alba, a small-flowered var. and a large-flowered var. are morphologically quite similar, the only difference being in the size of the different plant parts and flowers. The chromosome number of small-flowered var. was 2n=36 and that of large-flowered var. was 2n=54. This shows that the large-flowered variety is a triploid and has been derived from small-flowered variety by a change in ploidy level. Further investigations on the karyotypes of these varieties revealed marked similarities of chromosome structure. This further supports the view that large-flowered, Plumeria alba is a autotriploid.
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  • Tsutsumi Nagamatsu, Shozo Noda
    1971 Volume 36 Issue 2 Pages 332-340
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    In Ophiopogon japonicus and its related O. ohwii, whose basic chromosome number is x=18, two forms of hypotetraploids, 4x-5 (2n=67) and 4x-4 (2n=68), were commonly found. These hypotetraploids were dis-tinguishable not only as to the chromosome number, but also as to the constitution of the nucleolar chromosomes. Among them, the form 4x-4 was divided into three subtypes by the constitution of nucleolar constrictions. The plants tested were collected in various localities ranging from Tokyo to Okinawa, and the form 4x-5 was found in the most collected plants of O. japonicus, and the three subtypes of the form 4x-4 in those of O. ohwii.
    The behavior of the meiotic pairings was almost the same in both the forms 4x-5 and 4x-4. The community to both forms was found in the high frequency of bivalent formation at MI, with infrequent occurrence of uni-, tri-, and quadrivalent formations. The frequency of fertile good pollen grains was relatively high in both forms. Furthermore, the progenies obtained from a form 4x-5 of O. japonicus revealed a preponderance of mother type plants under open-pollination. Based on the results of these findings it is highly probable that the hypotetraploids are established by a secondarily induced genetic balance at the aneuploidal level.
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  • A. S. Hans
    1971 Volume 36 Issue 2 Pages 341-345
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytomorphological studies of two species of Trema of family Ulmaceae revealed that T. orientalis with n=10 differed from the previous reports of n=18 and 20. In T. amboinensis, two cytotypes, one diploid (n=10) and the other 16-ploid (n=80) have been detected. The morphological differences possibly resulting from polyploidy have been brought out. The base number of the genus is suggested to be x=10.
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  • Asit B. Mukherjee, Lytt I. Gardner
    1971 Volume 36 Issue 2 Pages 346-348
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • S. R. Desai
    1971 Volume 36 Issue 2 Pages 349-353
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • Juan Carlos Stockert, M. E. Fernández-Gómez
    1971 Volume 36 Issue 2 Pages 354-358
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The morphology of the nucleolar material in the nuclei of multinucleate cells or groups of cells produced in Allium cepa roots by treatment with colchicine was studied with the aid of silver impregnation as well as staining with basic fuchsin. From the 20th hours of recovery in about one third of the aneuploid nuclei which had not succeeded in organizing the nucleolus and which revealed the presence of prenucleolar bodies, other larger bodies were observed with the morphological characteristics of pseudonucleoli. These pseudonucleoli showed a clear segregation between the argyrophilic and the basophilic components of the nucleolus.
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  • Hideo Toriyama, Syôiti Satô
    1971 Volume 36 Issue 2 Pages 359-375
    Published: June 25, 1971
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Optical microscopy: It is possible to distinguish the stimulated Mimosa motor cell from the non-stimulated one, based on fixation with Müller's fluid followed by methyl blue staining. The shrinkage of the protoplast is clearly visible after stimulation. Under these conditions the contents of the central vacuole can not be markedly discriminated from the protoplasm. By treatment with Weber-Edsall solution the contents of the central vacuole disappear. While, in the same condition the protoplasm remains at the periphery of the motor cell. By this technique, it is made possible to distinguish the contents of central vacuole from the protoplasm. There are scarcely any contents of the central vacuole observable in some cells, while the contents are more or less clearly visible in other cells. At any rate, it is suggestive of the contents of the vacuole in the motor cell dissolved with Weber-Edsall solution.
    Electron microscopy: Before stimulation, diffused fine fibrillar contents of the central vacuole are clearly observable; they are 20-30mμ thick and 200-400mμ long. Upon stimulation, however the contents of the central vacuole change in appearance, becoming shrunken and aggregated pieces.
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