CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 31 , Issue 2
Showing 1-14 articles out of 14 articles from the selected issue
  • R. Natarajan, J. B. Burch
    1966 Volume 31 Issue 2 Pages 109-116
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    This paper presents the chromosome numbers of 7 species of primitive basommatophoran snails and discusses these numbers in relation to systematics and to those numbers reliably reported for the Archaeopulmonata by other authors.
    1. Sixteen bivalents were observed in cells of the first division of meiosis in the 4 species of Siphonariidae studied, Siphonaria alternata, S. guamensis, S. laciniosa and S. pectinata.
    2. Several different chromosome numbers were observed in the two species of Ellobiidae studied. Seventeen bivalents were observed in Cassidula vespertilionis and 19 pairs of chromosomes were found in Melampus coffeus and in a population (of hybrids?) resembling this species but differing slightly on shell morphology. One specimen in this latter population was a tetraploid individual with 38 bivalents.
    3. The one species of Chilinidae examined, Chilina fluviatilis, had 18 pairs of chromosomes.
    4. The caryotype of Melampus bidentatus lineatus consists of 7 pairs of metacentric chromosomes and 11 pairs of submetacentric chromosomes. This is the first accurate report of the caryotype of an ellobiid snail.
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  • II. Cytology of Rastrococcus iceroyides (Green) (Pseudococcidae-Coccoidea)
    T. S. S. Dikshith
    1966 Volume 31 Issue 2 Pages 117-124
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The cytology of Rastrococcus iceroyides (Green) has been worked out. The diploid number of chromosomes in both the sexes of this species is 10. In the male, two sets of chromosomes have been witnessed: 5 chromosomes are euchromatic and 5 other are heterochromatic in nature; and their differential behaviour during male meiosis has been discussed. The H-set has presented polymorphic shapes and configurations. Spontaneous chromosome fragmentation has also been observed and discussed.
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  • Chromosome pairing in an intervarietal hybrid of O. perennis Moench
    R. N. Misra, S. V. S. Shastry
    1966 Volume 31 Issue 2 Pages 125-131
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Pairing at pachytene and later stages in the F1 hybrid O. perennis var. balunga×O. perennis var. cubensis was normal except for loosely paired segments wherein the constituent chromosomal region are only secondarily associated but not relationally coiled. Nucleolar bivalents of the two varieties seem to be different and this accounts for the variable and high number of bivalents attached to the nucleolus which assumes abnormal shapes.
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  • V. Studies on sympathetic ganglion cells
    T. R. Shantha, G. H. Bourne
    1966 Volume 31 Issue 2 Pages 132-143
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The morphology of the TPPase-positive Golgi material has been studied in detail in the cells of the superior cervical sympathetic ganglia. In this study it was shown that the Golgi apparatus may take any shape or size. The stainability of the Golgi complex was also variable depending on the type of cell. Some cells contained a reticular network type of Golgi apparatus, some contained vesicles, vacuoles, and granules, and others contained predominantly large, round and oval masses. Based on these observations the spinal ganglion cells are grouped into three types. It has been suggested that the cells in each group undergo phasic activity in which the amount and stainability of the Golgi network gradually increases until it reaches a peak and then decreases. The TPPase-positive reaction was also variable indicating that the different cells are in different states of functional activity. The significance of these three groups of cells are briefly discussed in relation to their function and their specific cholinesterase content.
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  • B. N. Chowdaiah, Richard H. Baker, J. B. Kitzmiller
    1966 Volume 31 Issue 2 Pages 144-152
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    A standard salivary chromosome map is presented for Anopheles vestitipennis, based upon a population collected in the state of Vera Cruz, Mexico. It is proposed that this serves as the “standard” map for this species. Certain similarities of banding pattern, particularly at the ends of the autosomes, are evident between vestitipennis and the Holarctic Maculipennis species.
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  • Prem P. Jauhar, A. B. Joshi
    1966 Volume 31 Issue 2 Pages 153-159
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytology of four species of Panicum, viz., P. antidotale, P. cymbiforme, P. decompositum and P. repens, is described here. A variety of cytological techniques was tried and a suitable technique of fixation and cytological analysis for this material is described.
    The first two species with 2n=18 chromosomes behave as true diploids showing very regular cytological behaviour.
    The tetraploid taxon P. decompositum (2n=36) has proved to be very interesting cytologically. The chromosomes mostly associate as bivalents. About 10 per cent of the PMC's show the persistence of nucleolus till late metaphase I. Another interesting feature of this species is the presence of pronounced, clear and consistent secondary association of bivalents both at diakinesis and metaphase I. The bivalents tend to form 9 groups indicating x=9 as being the basic number for this species. The predominantly bivalent pairing (96 per cent of the cells), conspicuous absence of quadrivalent formation and the presence of heteromorphic bivalents both at diakinesis and metaphase I indicate the allotetraploid nature of this species.
    The present material of P. repens shows the presence of 36 chromosomes which tend to associate largely as bivalents. The frequency of quadrivalent formation is too low to consider this taxon as autotetraploid. The occurrence of chromosome mosaicism, univalents at diakinesis and metaphase I, and the presence of chromatin bridges at the anaphase and the telophase stages indicate structural hybridity. It appears, therefore, that the species may be a segmental allotetraploid.
    The role of hybridization and polyploidy in the evolution of the species under investigation is discussed.
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  • R. S. Rana
    1966 Volume 31 Issue 2 Pages 160-165
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytological observations on several populations of Chrysanthemum carinatum revealed the presence of two types of plants: those regularly forming nine bivalents (homozygotes for the standard or the rearranged karyotype) and others showing a multiple of four chromosomes along with seven bivalents (interchange heterozygotes). These two chromosomal types were compared with regard to their reproductive potential and it was found that the interchange heterozygotes produced more flowers and seed per plant than the homozygotes. It is concluded that the preponderance of interchange heterozygotes in these populations is determined primarily by their superior reproductive fitness.
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  • L. M. Srivastava
    1966 Volume 31 Issue 2 Pages 166-171
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Effect of paradichlorobenzene on somatic chromosomes of Vicia faba, V. narbonensis, V. hirsuta, Pisum arvense and Lathyrus sativus was studied after giving a prolonged treatment. Various mitotic anomalies were encountered. These included shortening and thickening of chromosomes, precocious separation of chromatids, tetraploid cells, binucleate cells, chromosome bridges and chromosome breakage. The potentiality of PDB as a mutagenic substance had been emphasised and terms like PDB-treatment, PDB-mitosis and PDB-metaphase were suggested for convenient use. Chromosome breaks generally took place at the heterochromatic regions.
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  • R. L. Baker, D. T. Morgan, Jr.
    1966 Volume 31 Issue 2 Pages 172-175
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Five plants of maize having monosomic microsporocytes were isolated from the X1 following crosses of zb4Pwwbr1 by irradiated pollen carrying Zb4PwrBr1. Three plants were hemizygous for all three recessive markers in chromosome 1. Since the marked region contains the centromere and all dominant markers genes from the pollen parent were deficient, it was concluded that chromosome 1 was missing. Root-tips of two of the three plants were in division and were monosomic. Two other plants with 19 chromosomes in the pollen mother cells were also found. One plant had 19 chromosomes in the root-tips; mitosis was not obtained in the other. These two plants were not hemizygous for all three recessives in chromosome 1, suggesting that a different chromosome had been lost.
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  • S. Dana
    1966 Volume 31 Issue 2 Pages 176-187
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. Mature hybrids were raised from P. aureus×P. trilobus cross. Reciprocal combination failed to produce mature pods.
    2. The F1 plants resembled one or other parent in some characters and were intermediate between the two parents in others. The plants had on average 30.7 per cent pollen fertility and produced few pods with viable seeds.
    3. Structural heterozygosity with regard to duplication, inversion and translocation was noted during analysis of pachytene and later stages of meiosis in F1.
    4. Colchicine induced amphidiploid plants had on average 83 per cent pollen fertility and produced many pods with viable seeds. Preferential pairing of chromosomes was observed in meiosis of these plants.
    5. The genomic notation AA has been proposed for the two parental species.
    6. The role of hybrid inviability, weakness and sterility in isolation has been discussed. The hybrid sterility is haplontic and chromosomal in nature. The significance of structural alterations in speciation has been pointed out.
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  • Werner Gottschalk
    1966 Volume 31 Issue 2 Pages 188-198
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    From the seeds of diploid and tetraploid tomatoes germinated on colchicine agar a small number of tetraploid and octoploid plants was obtained. Some of them showed manifold meiotic irregularities in addition to the usual cytological disturbances of polyploids. In the present paper degeneration of chromosomes and spindle anomalies are described.
    A direct correlation between regulative and degenerative processes could be observed in many aneuploid pollen mother cells of our polyploid material. A seperation of complete euploid chromosome complements took place while the supernumerary chromosomes of these cells degenerated. Thus, a genomatically balanced euploid final situation was formed starting from an unbalanced aneuploid initial situation.
    Manifold spindle abnormalities some of them being again correlated with genomatic regulation cause atypical courses of meiosis.
    The meiotic irregularities observed do not show a random distribution within the anther but they are accumulated in distinct areas. This “nestformation” is interpreted as a consequence of local metabolic disturbances in the tapetum tissue. The frequency of meiotic irregularities varies widely if we compare different plants of the same level of ploidy. Therefore, our material can be subdivided in cytologically stable plants showing a nearly normal meiosis and cytologically instable plants containing a wide spectrum of meiotic irregularities.
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  • Karel Janácek, Renata Rybová
    1966 Volume 31 Issue 2 Pages 199-202
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • Jay D. Mann, William B. Storey
    1966 Volume 31 Issue 2 Pages 203-207
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    IPC (O-isopropyl N-phenyl carbamate), CIPC (isopropyl N-(3-chlorophenyl) carbamate), and barban (4-chloro-2-butynyl N-(3-chlorophenyl) carbamate) are selective herbicides which inhibit growth of young seedling plants without causing immediate death. We find these compounds useful in making determinations of plant chromosome number and studies of their morphology in root tips. Treatment is with aqueous solutions ranging from 2.5 to 80 ppm for periods of 0.5 to 6 hours, followed by staining by the aceto-orcein squash method. IPC and CIPC cause mitotic activity to cease almost immediately. Chromosomes undergoing mitosis contract, in all species of plants studied, including some that have been reported to show no response to colchicine, 8-hydroxyquinoline, para-dichlorobenzene, and other chemicals used for this purpose. Metabolic nuclei show changes, also, suggesting that the herbicidal action of these compounds may be due to inhibition of messenger RNA synthesis by the DNA template. Uniformly good results to date on many species of plants suggest that IPC and CIPC may well replace chemicals now commonly used for facilitating cytological studies of plant cells. They are decidedly less hazardous to health than colchicine, and considerably cheaper to use.
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  • James E. Trosko, J. Grant Brewen
    1966 Volume 31 Issue 2 Pages 208-212
    Published: June 25, 1966
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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