CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 46 , Issue 1-2
Showing 1-46 articles out of 46 articles from the selected issue
  • L. Gavrila, V. Soran, Saeed Ahmad, V. Bercea, C-ta Spîrchez, F. ...
    1981 Volume 46 Issue 1-2 Pages 1-13
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • Kwong-yu Chan, L. S. Ling Wong, P. K. Wong
    1981 Volume 46 Issue 1-2 Pages 15-26
    Published: June 25, 1981
    Released: March 19, 2009
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  • L. S. Gill
    1981 Volume 46 Issue 1-2 Pages 27-44
    Published: June 25, 1981
    Released: March 19, 2009
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    Chromosome counts of 11 species and five hybrids from the Canadian material have been determined and their distribution maps are given. Five of these counts are new reports. The new basic chromosome numbers for two genera i.e. Collinsonia (x=13) and Hedeoma (x=19) have been suggested. Reproductive biology and the variational trends in these taxa have been studied. Keys to the Canadian species of three genera i.e. Hedeoma, Lycopus and Mentha have been provided. It has been proved that Lycopus virginicus does not occur in Canada.
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  • L. S. Gill
    1981 Volume 46 Issue 1-2 Pages 45-55
    Published: June 25, 1981
    Released: March 19, 2009
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    Chromosome numbers of 10 Canadian species have been determined and two of these counts are recorded for the first time. Reproductive biology and the variational trends in these taxa have been studied. Specific keys and the distribution maps are given. Pycnanthemum virginianum is found to be apomictic in Canada.
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  • Wilma S. Reese, A. J. Pappelis, G. A. Pappelis
    1981 Volume 46 Issue 1-2 Pages 57-61
    Published: June 25, 1981
    Released: March 19, 2009
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    Nucleolar dry mass and area means of inner epidermal cells in the equatorial region of white onion bulbs were compared with those 15 to 20 mm from the wound 48 hr later. Both nucleolar traits increased during the 48 hr as follows: dry mass of two nucleoli per nucleus, 83%; and, the area of two nucleoli, 60%. After the bulb was inoculated with a weakly pathogenic isolate of Aspergillus niger, means for nucleoli in the adjacent 4 cm increased 62% for nucleolar dry mass and 40% for nucleolar area. Because nucleoli in host cells respond positively to both wounding and inoculation, the effect of aggressive fungal pathogens on these cells and their organelles should be compared with that from cells collected from the inoculation site at the time of wounding. Nucleolar shape changes following wounding or inoculation suggests activation of the nucleolar organizer region to form bumb-bell type nucleoli which can cause interpretational problems when numbers and sizes of nucleoli per nucleus are being studied.
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  • Swarnjit Singh, P. K. Gupta
    1981 Volume 46 Issue 1-2 Pages 63-67
    Published: June 25, 1981
    Released: March 19, 2009
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  • A. Sheriff, Usha Gopala Rao
    1981 Volume 46 Issue 1-2 Pages 69-74
    Published: June 25, 1981
    Released: March 19, 2009
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    Scilla indica is widely distributed in central and southern parts of India and Sri Lanka, and is highly polymorphic, different populations in different geographical areas of the country looking like different species. Cytological studies on two phenotypically different populations of S. indica occurring in the Madras coastal areas have clearly revealed that both have the same chromosome number of 2n=45 and evidently represent naturally occurring triploids fitting very well under the established basic chromosome number of 15 for the species in the country. These were mistaken to be diploids (aneuploid races) with 2n=44, 45, 46 by the earlier workers apparently due to the reason that the diploid number of 2n=30 was not known at that time. The present study has also revealed the existence of two kinds of triploids in the area, the broad leaved variety consisting of autotriploids and the narrow-leaved variety consisting of allotriploids. While the autotriploids have chromosomes similar to those found in their diploid counterparts, the allotriploids are unique in their diploid set having two long chromosomes with subterminal primary constrictions, a type not encountered in any of the Indian Scillas but very common in European Scillas. Both populations are sexually sterile. Nevertheless, they are found well established with effective means of vegetative propagation through prolific production of bulbils at the leaf tips and underground daughter bulbs. Cytogeographically these populations are very interesting in that they are found restricted and isolated in the coastal areas of Madras in India with no other kind of Scilla other than these triploids occurring in the area. It is also significant to record that in no other area in the country except Madras, did the authors come across any naturally occurring triploids of this species.
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  • L. D. Meshram, M. N. Narkhede, N. Y. Deshmukh
    1981 Volume 46 Issue 1-2 Pages 75-79
    Published: June 25, 1981
    Released: March 19, 2009
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    A plant having spontaneous multiple translocations was isolated in the normal populations of Chilli cultivar CA-960. The plant was very healthy having broad green leaves and big size flowers. The chromosome behaviour was studied from the anther smears. At metaphase I rings of 4 and 8 chromosomes and chains of 4, 6, 8, 10, 12, and 18 chromosomes were observed in most of the microsporocytes studied. Regular formation of bivalents and univalents were also noted. Nondisjunction and irregular distribution of chromosomes, laggards and chromatin bridges were observed at anaphase I.
    All these irregularities lead to the formation of unbalanced spores resulting in 90 to 100% sterility. The probable reasons for these anomalies are discussed.
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  • Seiichi Sato
    1981 Volume 46 Issue 1-2 Pages 81-87
    Published: June 25, 1981
    Released: March 19, 2009
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    In the chromosomes of Nothoscordum fragrans, the C-banding positive segments were found to be composed of dot-like compartments (C-positive dots). Three groups of C-banding positive segments could be distinguished by the organization of the C-positive dots: the I-segments were generally composed of four C-positive dots, which were linearly arranged across the width of the metaphase chromosomes, while the S-segments of each sister chromatid were completely C-banding positive and generally appeared as double C-positive dots at metaphase and a single dot at anaphase, and the M-segments of the metaphase chromosomes were almost always composed of two C-positive dots each of which was located on the edge of a sister chromatid. The number of C-positive dots for each C-banding positive segment varied depending on the cell cycle. The differentiation of the C-positive dots across the width of the chromosomes is discussed with respect to the chromosomal structure.
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  • On the differential chromosome pairing in colchiploid stock of Tephrosia wallichii
    P. K. Srivastav, S. N. Raina
    1981 Volume 46 Issue 1-2 Pages 89-97
    Published: June 25, 1981
    Released: March 19, 2009
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    Colchicinization in Tephrosia wallichii was achieved in 5 out of 64 treated seedlings. Among them two types of cyto-colchiploids were recognized, one showing lack of pairing or crossing over (desynaptic), and the other behaved like a normal autotetraploid, though quadrivalent frequency was very low. In December 1977, 18 out of 20 PMCs analysed, showed complete lack of pairing (44I) in desynaptic cyto-colchiploids, whereas the other type had normal pairing leading to multivalent associations, bivalents and few univalents. In subsequent meiotic analysis in May and August 1978, significant increase in pairing of chromosomes in desynaptic cyto-colchiploids was observed, whereas the other cyto-colchiploids behaved as before.
    It is concluded that differential behaviour of colchiploids at meiosis may be attributed to that the seeds used for colchicinization may be genetically not exactly similar and desynaptic cyto-colchiploids may have been desynaptic even at diploid level, which may be genic rather than chromosomal in nature.
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  • VII. Karyotypes of 13 species from the southern United States
    J. R. Gold, W. D. Womac, F. H. Deal, J. A. Barlow, Jr.
    1981 Volume 46 Issue 1-2 Pages 105-115
    Published: June 25, 1981
    Released: March 19, 2009
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    We have examined karyotypes of 13 species from eight genera of cyprinid fishes endemic to North America. All thirteen have diploid complements of 50 chromosomes. Arm numbers were estimated for ten species and varied from 46-50 (haploid). The pattern and extent of karyotypic diversity among these 13 species is typical of all North American cyprinids assayed to date. Almost all species have n=25 chromosomes, and variation in arm number is minimal. The conservatism in gross karyotype among these fishes is not commensurate with their apparently rapid and extensive radiation, and suggests that major chromosomal change has played only a minor role in cyprinid evolution.
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  • M. R. Sudharshan, K. S. Jagadishchandra
    1981 Volume 46 Issue 1-2 Pages 117-123
    Published: June 25, 1981
    Released: March 19, 2009
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    Unusual cytological behaviour during microsporogenesis was observed in wild population of tetraploid C. caesius. A new phenomenon of incomplete cytokinesis by furrowing and nuclear fusion leading to 2n pollen formation has been described and discussed. Other meiotic irregularities recorded were the absence of cytokinesis, restitution nuclei formation leading to 2n pollen formation, attached tetrad cells, binucleate pollen and syncyte formation.
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  • P. A. Pool, Ruth Ingram, R. J. Abbott, D. L. Jennings, Pauline B. Toph ...
    1981 Volume 46 Issue 1-2 Pages 125-132
    Published: June 25, 1981
    Released: March 19, 2009
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    Previous workers have reported that Rubus chromosomes are too small for karyotype analyses at mitosis, and also that meiotic studies indicate no major structural differences between Rubus genomes. However, it was found possible to identify the seven chromosomes of Glen Clova, a cultivar of R. idaeus, and of R. coreanus. The chromosomes of R. idaeus differed from those of R. coreanus, four of them appreciably, and it was possible to identify each of the 14 chromosomes of four F1hybrids between the two species. In spite of these differences, meiosis and pollen formation in the hybrids appeared normal. It is suggested that genome differentiation in the genus is greater than realised, and that further karyotype analyses may aid studies of species relationships.
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  • Suniti Kumar Mandal, Rabindra Krishna Basu
    1981 Volume 46 Issue 1-2 Pages 133-139
    Published: June 25, 1981
    Released: March 19, 2009
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    Treatments with IAA and GA3 singly and especially after x-irradiation produced significant reduction in mitotic index in root meristem of Allium cepa.
    Pre-and post-irradiation treatments with IAA and GA3 also showed significant reduction in x-ray-induced chromosomal aberrations. The percentage of protection ranged from 18-55 with IAA and 14-53 with GA3. These growth hormones were considered to have reduced aberrant cells by providing protection against initial radiation damage and also by stimulating restitution presumably by affecting DNA synthesis and also by stimulating protein synthesis respectively.
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  • Karyomorphology and meiotic behaviour of Crinum zeylanicum L.-a new cytotype
    M. U. Patwary, M. A. Zaman
    1981 Volume 46 Issue 1-2 Pages 141-148
    Published: June 25, 1981
    Released: March 19, 2009
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    Consistent presence of 2n=22 chromosomes in RTCs apparently forming 11 homologous pairs, n=11 chromosomes in PMCs and high chiasma frequency indicate that Crinum zeylanicum studied here is a basic diploid (2n=2x). The somatic chromosomes, 5.47 to 14.52μm in length, had a centromeric formula of 6M+2NM+9SM+5NAC. The heteromorphicity in two pairs may be related to deletion or duplication or both rather than to hybrid origin of the plant. The present results being different in many features from those reported by others on C. zeylanicum seem to favour the idea that the plant studied by us may represent a new cytotype.
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  • Chromosome number and karyotype analysis of Thespesia, Hibiscus, Abelmoschus, Pavonia and Malachra
    Aparna Dasgupta, R. P. Bhatt
    1981 Volume 46 Issue 1-2 Pages 149-160
    Published: June 25, 1981
    Released: March 19, 2009
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    Five genera of the family Malvaceae are considered for the present work. On the basis of the cytological work 3 genera of the tribe Hibisceae studied can be arranged in the following evolutionary sequence i.e. Thespesia, Hibiscus and Abelmoschus. In the tribe Ureneae the studies of two genera show the evolved nature of karyotype of Malachra capitata over Pavonia. The most primitive nature of the karyotype is found in Thespesia populnea having 2n=28 suggest number 7 can be a base numbers.
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  • S. M. Handa, Pushpinda Kaur, Sarbjit Kaur, Harmohinder Kaur
    1981 Volume 46 Issue 1-2 Pages 161-167
    Published: June 25, 1981
    Released: March 19, 2009
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    The present investigations deal with the mapping of eleven salivary chromosome arms of Chrysomyia megacephala (Calliphoridae: Diptera). The various arms correspond to five autosomal pairs and one sex chromosome-X found in its germ cells. The presence of the Y-chromosome arm could not be observed. The various arms have been designated and classified arbitrarily. The entire chromosomal complement has been divided into 47 zones. There is also present a weak and fragile chromocentre.
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  • I Chromosome aberrations in Vicia faba
    G. D. E. Njagi, H. N. B. Gopalan
    1981 Volume 46 Issue 1-2 Pages 169-172
    Published: June 25, 1981
    Released: March 19, 2009
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    The insecticides: summithion, lannate, carbicron, thiodan and kelthane, the fungicides: diathane M-45 and aladrin and the herbicides: ramrod, lasso, round up and grammoxone induce acute mitostatic effects of Vicia faba root meristematic cells. Pycnotic nuclei and premature chromosome condensation are also evident. Also carbicron, kelthane, lasso and ramrod induce anaphase bridges accompanied by relatively scarce micronuclei. The results suggest possible genetic damage by these chemicals.
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  • P. N. Mehra, Subhash C. Khitha
    1981 Volume 46 Issue 1-2 Pages 173-181
    Published: June 25, 1981
    Released: March 19, 2009
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    The karyotype of Ephedra foliata-a strictly dioecious species, has been studied from root tips, stem apices, female gametophyte and male gametophyte.
    The haploid set consist of seven chromosomes in a 1 M+3m+1sm+2st arrangement i.e. 5V's+2J's. From among the 5V's two chromosomes one with Median point primary constriction (M) and one with a median region primary constriction (m) are satellited, the satellite in the latter case being on the short arm. Meiotic and karyotypic studies lend a strong evidence that the sex determining mechanism in this plant is related to satellites in the Metacentric pair CC. In female plants the two homologues of this Metacentric pair have two satellites one on each arm i.e.V V, whereas in the male plants one homologue has two satellites (one on each arm) while the other has it only on one arm i.e.V V.
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  • S. C. Sadhukhan, S. K. Banerjee
    1981 Volume 46 Issue 1-2 Pages 183-193
    Published: June 25, 1981
    Released: March 19, 2009
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    Histochemical studies on the adrenal medulla and histochemical as well as histomorphic studies on the adrenal cortex were made in the garden lizard, Calotes versicolor at 4 hr and on days 1, 3, 5, 7, 15 and 30 following intraperitoneal injection of single sub-lethal doses (0.3, 1.0 and 5.0mg) of barbital sodium.
    The basic effect of this drug on the adrenal medulla is stimulation which is followed by inhibition and subsequent attainment of normal level of activity. The lowest dose activates the adrenal cortex for a longer period while the other two doses increase the adrenocortical activity that alters with normal level of activity. The changes, however, do not seem to be related with doses and periods.
    Complete recovery from the effect of this drug on the medulla is seen on the 1st day (0.3mg), 5th day (1.0mg), and 30th day (5.0mg) while on the cortex it is seen on the 30th day (0.3 and 1.0mg) and 15th day (5.0mg) following the treatment.
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  • K. V. Bhavanandan
    1981 Volume 46 Issue 1-2 Pages 195-207
    Published: June 25, 1981
    Released: March 19, 2009
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    Cytological investigation on 46 taxa belonging to 43 species under 14 genera of South Indian Aspidiaceae has been carried out. Chromosomal variations such as hybridity, aneuploidy, polyploidy and supernumerary division following meiosis have been encountered, The occurrence of species complexes has been detected in Arachnoides aristata and Cyclosorus interruptus. Bolbitis quoyana, Diplazium silvaticum, Tectaria paleocnemoides and T. decurrens var. minor have been found to be natural hybrids and the possible origin of the former three species has been suggested. Fifty per cent of the total 46 taxa investigated was found to be polyploids. Aneuploid changes in chromosome number have been detected in Thelypteris and Dryopteris. The origin of the different basic numbers in the genus Thelypteris has been discussed. It has been inferred from the present investigation that cytological changes like hybridity, polyploidy and aneuploidy have played an important role in the evolution of the Aspidiaceous ferns in South India.
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  • J. P. M. Camacho, J. C. Orozco, F. Pascual
    1981 Volume 46 Issue 1-2 Pages 209-215
    Published: June 25, 1981
    Released: March 19, 2009
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    An hypothesis has been put forward to explain the differences observed between the karyotype of three species of Decticinae from the Iberian Peninsula. The chromosome rearrangements that have played a role in the evolution of this orthopteran group have been the centric fusion and the pericentric inversion.
    Furthermore, a new species is cited with a neo-XY sex-chromosome mechanism within the superfamily Tettigonioidea. This species is the tenth case of tettigoniid carrying B-chromosomes found hitherto in this superfamily.
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  • Ram S. Verma, Ming S. Lin
    1981 Volume 46 Issue 1-2 Pages 217-224
    Published: June 25, 1981
    Released: March 19, 2009
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    The duration of DNA Synthesis period (S) is estimated by three different methods by autoradiography with 3H-TdR in Zea mays L. root meristem cells. It is concluded that the three methods yielded similar results. It is presumed that the accuracy of estimating S period by any of three methods depends on the sample size and the mechanics of plotting the curve. The duration of DNA Synthesis was prolonged in roots treated with cycloheximide, chloramphenicol, mitomycin C (MC) or hydroxylamine sulphate (HAS). The incorporation of 3H-TdR) after treatment with MC and HAS was also observed. It was found that MC reduces the incorporation of the radioactive precursor (3H-TdR) into DNA, not only during the time of treatment, but also after the treatment. HAS was also found to inhibit the incorporation of 3H-TdR into DNA but the incorporation increased soon after the removal from HAS. The action of HAS on inhibition of DNA Synthesis is different from that of MC. Furthermore, it was found that the effect of HAS on nhibition of DNA Synthesis is easily reversible.
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  • Maria José Lima da Silva
    1981 Volume 46 Issue 1-2 Pages 225-232
    Published: June 25, 1981
    Released: March 19, 2009
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    Nuclear Feulgen-DNA values were cytophotometrically evaluated in the various zones of the salivary glands of Bradysia spatitergum at the 1st and early 4th larval instar and prepupal stage. The smallest and largest duplication intervals for the Feulgen-DNA values, both ascribed to be provided by polytenization phenomena, were found in the S1 and S2 regions of the glands, respectively. They are possibly related with different secretion activities of these glandular regions.
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  • P. Raicu, Elena Taisescu, P. Banarescu
    1981 Volume 46 Issue 1-2 Pages 233-240
    Published: June 25, 1981
    Released: March 19, 2009
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  • W. W. K. Cheung
    1981 Volume 46 Issue 1-2 Pages 241-254
    Published: June 25, 1981
    Released: March 19, 2009
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  • H. C. Choudhuri
    1981 Volume 46 Issue 1-2 Pages 255-264
    Published: June 25, 1981
    Released: March 19, 2009
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    The haploid and diploid number of chromosomes in S. melongena var. Giwa-2×var. Giwa-1 is found to be 12 and 24, respectively. The chromosomes exhibit differences in size and their morphology, having metacentric and submetacentric centromeres.
    In meiosis pairing begins at a point near the centromere and generally passes along the length of the chromosomes. Where three of four homologous segments of chromosomes lie together, pairing appeared in two of the three or four chromosome threads in a particular segments. Pairing is allosyndetic, 12 chromosomes of Giwa-2 pairing with 12 chromosomes of Giwa-1.
    Frequencies of chiasmata at diplotene and diakinesis are analysed. The frequency per bivalent at diplotene and diakinesis varied from 1.91 to 1.28, respectively.
    Multivalent chromosomes in form of quarivalents and trivalents occurred in 31.9 % cases observed. The occurrence of high frequency of multivalents in a diploid hybrid seemed to indicate the presence of translocation interchanges in S. melongena var. Giwa-2×var. Giwa-1.
    The univalents occurred in 29.8 % cases observed. Structural changes are probably responsible for failure of pairing among pairable chromosomes. The behaviour of univalents varied, they either pass to the poles or lag (18.4%) or eliminated (11.4%). The elimination of univalents causes unequal distribution of chromosomes on second metaphase plates. Univalents and fragments failed to be included in the daughter nuclei formed micronuclei.
    The high frequency of pairing of chromosomes in the hybrid indicates that two varieties of S. melongena, Giwa-1 and Giwa-2 are closely related.
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  • I Genus Paspalum
    P. N. Mehra, J. D. Chaudhary
    1981 Volume 46 Issue 1-2 Pages 265-278
    Published: June 25, 1981
    Released: March 19, 2009
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    Male-meiosis in 8 species of the genus Paspalum is studied. P. canarae (n=9) is investigated for the first time and it is the only diploid in the genus based on x=9. New cytological races have been detected in P. dialatatum (2n=60) and P. arbiculare (2n=60). The genus is suggested to be dibasic with x=9, 10. Desynapsis accom-panied by non-reduction is observed in P. conjugatum (2n=40), P. dilatatum (2n=60), P. longifolium (2n=40) and P. orbiculare (2n=60). All of them are suspected to be apomicts.
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  • II. Karyological studies in twelve species
    V. B. Kulshreshtha, P. K. Gupta
    1981 Volume 46 Issue 1-2 Pages 279-289
    Published: June 25, 1981
    Released: March 19, 2009
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    Karyotypes were prepared in twelve species ofHelianthus utilizing root tip metaphase mitoses. Ten species were diploid with 2n=34, H. mollis was diploid with 2n=30 and H. tuberosus was hexaploid with 2n=102. The mean chromosome length between species ranged from 2.2μto 3.5μ, although within a species individual chromosomes could be as small as 1.1μ and as long as 5.2μ. The karyotypes in eight species were presented for the first time and the results in the remaining four species are discussed in view of the earlier published results.
    It is concluded that structural changes did not alter the karyotypes to any appreciable degree, since ten of the twelve species were placed in class 2B of Stebbins. Only H. annuus and H. mollis were placed in class 1 B.
    Karyotype of H. tuberosus was examined and two of the three genomes taking part in its constitution were tentatively assigned to H. annuus and H. lenticularis.
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  • II. Cytomorphological studies in hybrid G. hirsufum haploid (2n=2x=26, AhDhG. thurberi (2n=2x=26, D1D1)
    M. V. Thombre, S. S. Mehetre
    1981 Volume 46 Issue 1-2 Pages 291-299
    Published: June 25, 1981
    Released: March 19, 2009
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    A new interspecific hybrid (2n=26) AhDhD1/2 has been obtained by crossing G. hirsutum L. haploid (2n=2x=26, AhDh) with G. thurberi Tod. (2n=2x=26, D1D1). Observations on its morphological characters and cytology have been recorded. The hybrid was found to be highly vigorous and fairly fertile. The characters in F1 like leaf shape, gossypol glands boll bearing and shape, rind thickness and earliness of G. thurberi which are associated with bollworm tolerance and other economic characters like plant habit, bract shape, flower colour and shape, anther arrangement, seed fuzz and presence of lint of G. hirsutum were found to be dominant. The F1 being fairly fertile it is likely to get segregants with different character combinations both on glanded and glandless background. The possibility of incorporating insect resistance in glandless lines has been indicated.
    From the chromosome analysis in this plant it was observed that D1 chromosomes of G. thurberi show greater homology with AhDhchromosomes resulting in formation of on an average 8.8 bivalents per cell and thus high degree of fertility.
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  • K. J. Madhusoodanan, M. A. Nazeer, G. V. Subrahmanyam
    1981 Volume 46 Issue 1-2 Pages 301-305
    Published: June 25, 1981
    Released: March 19, 2009
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    In an individual belonging to one of the diploid garden races of Phlox drummondii Hook. (2n=14), in 30% of the cells, four chromosomes instead of forming two bivalents at meiosis form an interchange association. Except for its heterotic behaviour, the translocation heterozygote was phenotypically indistinguishable from the homozygote. The chromosome complex was both of ring and chain type, the former being preponderant. At anaphase I, in the exclusively bivalent forming cells, disjunction of two of the bivalents was consistently late. The asymmetrical nature of the interchange as well as the involvement of the long arm of two non-homologous chromosomes of second and last pair of the complement is apparent from the two heteromorphic pairs in the karyotype. Pollen fertility and seed setting were near normal. The establishment of interchange heterozygosity is correlated with a change of breeding system from out-to inbreeding.
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  • V. S. Raman
    1981 Volume 46 Issue 1-2 Pages 307-321
    Published: June 25, 1981
    Released: March 19, 2009
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    Studies of chromosome pairing in interspecific hybrids and induced allopolyploids of Arachis elucidated the genomic structure of A. hypogaea and other tetraploid species. The diploid species (2n=20) probably originated from 10 chromosome (2n) ancestors as yet unknown. In view of the paucity of evidence from studies on diploid hybrids and their amphidiploids, the nature of genomic differentiation of the individual diploid species is not well understood at present. The chromosomes of the haploid complement of the diploid species have homeologous counterparts in the A and B genomes of the tetraploid species and a set of 5 chromosomes in one of the genomes of the latter appears to exhibit a high level of differentiation. In the allohexaploids which comprise the genomes of the tetraploid and diploid species, pairing seems to be enhanced by genetic mechanisms even to give maximum expression to the residual affinity. It is probable that the genotype of the diploid species brings in the accentuation of pairing due to a breakdown of diploidising factor present in the polyploids of Arachis.
    Triploid and tetraploid hybrids and the allohexaploid manifested multivalent chromosome pairing and aberrant meiotic behaviour. The realisation of balanced euploid derivatives in different proportions signified the organisation of gametes with three different chromosome numbers as a result of directed genomic segregation in the meiosis of the progenitor polyploids. Euselectivity of gametes in ferfertilization was also evidenced from the analysis of progenies resulting from backcrosses of A. hypogaea with the three synthetic polyploids. Auxiliary mechanisms arising from genomic combinations seemed to be effective in determining the breeding behaviour of the experimental polyploids. The deviations in the strength of expression of the genic mechanisms also appeared to depend upon the differences in the genomic composition of the interspecific hybrids and induced polyploids.
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  • III. Released nucleoplasm in the central cylinder of pea root tips
    Hideo Toriyama
    1981 Volume 46 Issue 1-2 Pages 323-330
    Published: June 25, 1981
    Released: March 19, 2009
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    In the present investigation, the released nucleoplasm in the central cylinder of primary root tips of Pisum sativum, variety “Alaska”, was studied from the cytological and histological view point.
    In the area about 900μm to 2000μm from the apical initials, there are two kinds of bodies of released nucleoplasm; one is thick and short (width 6-8μm, length 15-20μm), and the other is thin and long (width 4-5μm, length 20-25μ). The process of differentiation of this nucleoplasm from the procambial meristem of the central cylinder are observable in the area about 600μm to 900μm from the apical initials.
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  • I. Electron microscopic studies on the mitotic endosperm protoplast
    Akio Hanaoka
    1981 Volume 46 Issue 1-2 Pages 331-342
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Fine structures of the kinetochore and kinetochore fiber of the mitotic endosperm protoplasts in Zephyranthes are investigated based on their serial sections under electron microscope. The kinetochore is a protrusion adjacent to chromatin and forms a cylindrical structure with an outer diameter of 5-7×102nm. A typical kinetochore fiber is composed of a bundle of microtubules and each microtubule is approximately 24nm in diamter. Kf-MTs are developed from the bottom of the kinetochore. The number of Kf-MTs per one kinetochore is estimated 50-100. The arrangement of Kf-MTs is ring very near the kinetochore from which the microtubules keeping their ring orientation.
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  • I. Interphase chromosomes in three liliaceous plants
    Noriyuki Tanaka
    1981 Volume 46 Issue 1-2 Pages 343-357
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1.The mode of the chromosomal arrangement in interphase nuclei was investigated in the root tips of three liliaceous plants; Polygonatum lasianthum with large-, or medium-sized chromosomes (2n=20), Dianella ensifolia with relatively small-sized chromosomes (2n=32), and Tofieldia coccinea var. kondoi with smallsized chromosomes (2n=30). Both the C-banded and the unpressed preparations stained with aceto-orcein were used for this study.
    2. After C-banding treatment, the centromeric regions of all the mitotic chromosomes and the regions of the secondary constriction were deeply stained. Most of these C-banded segments also appeared in interphase nuclei.
    3. The centromeric regions tended to be located close to the inner surface of the nuclear envelope during the period from telophase to prophase.
    4. The relative extent of the distributional range of the centromeric regions in the nucleus, which was considered to extend from the center of the polar region of the nucleus, was found to be nearly constant for each species but different distinctly among the three species examined: That is, the relative extent of the distributional range was the smallest in P. lasianthum, and the largest in T coccinea var. kondoi.
    5. The mode of the chromosomal arrangement at telophase tended to be maintained during interphase and prophase.
    6. The relationship between the relative extent of the distributional range of the centromeric regions in the nucleus and the variability of the relative positions of chromosomes during the mitotic cycle was discussed.
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  • René Rohr
    1981 Volume 46 Issue 1-2 Pages 359-370
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    L'endosperme de Cycas revoluta sectionnéen plusieurs parties a été cultiveé in vitro sur un milieu synthétique solidifié. Après deux mois de culture seulement, une évolution remarquable des divers tissus gamétophytiques a pu être mise enévidence. Les tissus marginaux produisent des excroissances denses blanchâtres et les tissus internes du prothalle prolifèrent lorsqu'ils sont mis à l'air.
    Les differenéts tissus du méegagamétophyte sont étudiés au niveau ultrastructual: l'assise cellulaire externe se distingue des autres par une accumulation considérable de réserves lipidiques; dans les tissus sous-jacents, les réserves lipidiques décroissent et font place à des réserves amylacées dans les plastes et à des réserves intravacuolaires rappelant des réserves protéolipidiques. Enfin, le tissu interne ne contient pratiquement que de l'amidon en trés grande quantité.
    Cette étude montre en outre, que dans des conditions de culture in vitro appropriées, tous ces tissus spécialisés dans le stockage des réserves peuvent pourtant se dédifférencier. Dans tous les cas, cette évolution s'accompagne de la disparition partielle ou totale des réserves dans les cellules et d'une activation de la plupart des organites cellulaires.
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  • F. J. Novák
    1981 Volume 46 Issue 1-2 Pages 371-379
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The paper gives cytological and chromosomal characteristics of a long-term in vitro callus culture of garlic (Allium sativum L.). The changes in chromosome number and morphology have been observed in two callus lines- of meristem and leaf origin. In both cultures the frequency of polyploid mitoses is increasing with the age of the culture. The paper describes structural chromosomal changes and mitotic irregularities in callus cells. The causes of karyologic instabilities, occurring during in vitro culture, are discussed.
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  • Viorel Soran, Constanta Spârchez, Constantin Craciun, Zoltan Ura ...
    1981 Volume 46 Issue 1-2 Pages 381-386
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The root meristem of broad bean (Vicia faba) fourth day old with γ ray in doses of 50, 100, 200, 300 and 500 rad was irradiated. After 24 hours the root tip was fixed with glutaraldehyde and osmic acid and after that embedded in W vestopal. On several sections micronuclei were present and their ultrastructure could be studied. From ultrastructural point of view the heterochromatinic micronuclei are acentric chromosomal fragments and the euchromatinic ones probably not. A clear separation between micronuclei and other fragments of the normal nucleus was proved.
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  • P. Bastide, M. F. de Rocca Serra, N. Fellmann, J. Y. Jaffray, A. Genei ...
    1981 Volume 46 Issue 1-2 Pages 387-391
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    L'action de 9 substances antimitotiques utilisées in vitro à des doses proches des doses thérapeutiques a été testée sur des cultures lymphocytaires humaines.
    Diverses lésions ont été observées sur les noyaux et les chromosomes. 1) Les alkylants: cyclophosphamide, ifosfamide, chloréthazine déterminent des chromomérisations et étirements. D'autres agents à propriétés alkylantes: mytomycine et actinomycine D, entraînent en outre des lacunes et des cassures. 2) Les antimétabolites, analogues des bases pyrimidiques (5 bromodesoxyuridine, cytosinearabinoside) induisent régulièrement des chromomérisations chromatidiennes avec images de“banding”.
    3) Les dérivés des alcaloides (teniposide) par blocages mitotiques en prophase ont une action proprement nucléaire, avec création d'anisonucléose, chaÎns nucléaires, condensations chromatidiennes.
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  • Tomosaburo Yabuno
    1981 Volume 46 Issue 1-2 Pages 393-396
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    A French strain that was collected in a paddy field and has been referred to E. phyllopogon was morphologically and cytologically examined. Judging from Kossenko's description, the French strain could be referred to E. phyllopogon Stapf subsp. oryzicola (Vasing.) Koss. var. genuina Koss., and was confirmed to be a tetraploid, with n=18.
    On the other hand, with respect to the principal morphological characters, the French strain of E. phyllopogon was not distinguishable from F-form of tetraploids species E. oryzicola Vasing. (n=18).
    Meiosis of the F1 hybrid of the French strain with E. oryzicola was normal and 18 bivalents were observed, and pollen and seed fertilities were as high as those of the parents. Thus the French strain and E. oryzicola could not be cytologically separated.
    Based on the morphological and cytological evidences, E. phyllopogon subsp. oryzicola was considered as a synonym of E. oryzicola.
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  • L. Janardhana Reddy
    1981 Volume 46 Issue 1-2 Pages 397-412
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The individual pachytene chromosomes of the entire complement of Cajanus cajan and Atylosia lineata were identified on the basis of relative length, arm ratio, chromomere pattern and nucleolar association. The pachytene chromosomes of both the species were found to belong to the differentiated type. Cajanus possesses 2 median, 6 sub-median and 3 subterminal chromosomes and A. lineata, 2 median, 7 sub-median and 2 subterminal chromosomes. On the basis of the various criteria employed for the identification of pachytene chromosomes, 10 chromosomes were found to be common to both Cajanus and A. lineata.
    In the Cajanus×A. lineata hybrid a considerable number of microsporocytes, at pachytene, revealed complete synapsis. This indicates a very high degree of homology between the two genera. In the hybrid, in nine out of the eleven bivalents the homoeologues participating in synapsis were identified. No major structural alterations were evident from the pairing behaviour and two bivalents exhibited heteromorphism in the hybrid. These studies indicate that indeed Cajanus and Atylosia lineata are closely related to each other.
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  • I. Studies in seven transfers from the 1812th to 1895th generations
    Yoshitaka Obara, Hitoshi Satoh, Kazuo Saitoh
    1981 Volume 46 Issue 1-2 Pages 413-426
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Chromosomes of the Usubuchi sarcoma cells are investigated in some detail, use being made of banding techniques, in seven samples from the 1812th to 1895th transfer generations. The sarcoma is regarded as a hypertriploid tumor in the generations examined, with a modal number of 65. This hypertriploid tumor scarcely comprizes in its chromosome complement disomic or trisomic homologues, as well as the normal rat chromosomes. The karyotypic constitution of the US cells is quite different numerically and morphologically from that of the normal rat karyotype. Seven chromosomes with unusual morphology are remarkable in occurrence as markers. In three of them (M5, M6 and M7), their possible derivation is traced on the basis of their characteristic banding patterns. The combination of the markers widely varies from cell to cell even in the sample from the same transfer generation. Their combination pattern seems to be irrelevant to either the number of chromosomes or the transfer generation.
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  • Miwako Saito
    1981 Volume 46 Issue 1-2 Pages 427-430
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Concanavalin A-mediated cell surface changes during development have been studied in four species of the cellular slime moulds, Dictyostelium discoideum, D. mucoroides, D. purpureum and Polysphondylium violaceum. Strains belonging to the same species showed a similar pattern of changes during the course of development. The pattern was similar for D. discoideum and D. mucoroides. These two species showed a gradual decrease in Con A-mediated cell agglutination as development proceeded. In D. purpureum and P. violaceum, however, the cell agglutinability increased at the beginning of development and then decreased thereafter. The results therefore indicate that cell-surface changes during development are species-specific.
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  • I. A new-shaped chromosome
    Yoshihiko Yonezawa
    1981 Volume 46 Issue 1-2 Pages 431-441
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. In the inbred line of Haplopappus gracilis KH-1 (2n=4), a new-shaped chromosome was found. The length of this chromosome was similar to chromosome 1 and this is J-shaped chromosome having centromere at the subterminal position.
    2. From the distribution of the early condensing regions at mitotic prophase and the meiotic chromosome behaviour of the heterozygotes of J-shaped and V-shaped chromosome, it was suggested that the J-shaped chromosome was derived from the V-shaped chromosome by the appearance of a new centromere in the subterminal position and by the disappearance of the centromere in the median position.
    3. The cause of the appearance of the new centromere in this chromosome was presumed to be an actuation of the suppressed centromere in the subterminal position and a suppression of the median centromere.
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  • II. Genetic behaviour of the new-shaped chromosome
    Yoshihiko Yonezawa
    1981 Volume 46 Issue 1-2 Pages 443-449
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. The inheritance and genetic influence of the J-shaped chromosome found in Haplopappus gracilis (2n=4) was studied.
    2. The frequency of JJ-type progenies obtained from the inbreeding of VJ-type was very low, lower than that of expectation. This suggests that some lethal effects are induced in some of the JJ-homozygotes.
    3. From the crossing of VJ-type with VV-type, it is suggested that pollen grains with J-shaped chromosome may be inferior to pollen grains with V-shaped chromosome on VV-homozygous pistile.
    4. Karyotype analysis of the clones in the experimental population showed that the VJ-heterozygotes gradually increased, while the VV-homozygotes gradually decreased and very few JJ-homozygotes occurred. This suggests that the VJ-heterozygotes are advantageous than VV-homozygotes, and that the JJ-homozygotes are disadvantageous. Therefore, the J-shaped chromosome is presumed to have a strong influence when combines with V-shaped chromosome.
    5. The flowering season of JJ-combination was delayed for about one month as compared with those of VV- and VJ-combinations. This delay of the flowering season may cause the reproductive isolation of JJ-combination from the other combinations, thus resulting in the differentiation of a new karyotype.
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  • R. Riehl
    1981 Volume 46 Issue 1-2 Pages 451-453
    Published: June 25, 1981
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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