CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 51 , Issue 4
Showing 1-28 articles out of 28 articles from the selected issue
  • Judith K. Greenlee, Karamjit S. Rai
    1986 Volume 51 Issue 4 Pages 631-636
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Karyotype analysis of Collinsia verna and C. heterophylla revealed seven pairs of chromosomes with a decrease in length of chromosomes across each genome from approximately 11 microns to 5 microns. The smallest pair is knobbed in both species. A change in centromere position in the two longest chromosomes between the two species is indicative of the presence of chromosomal rearrangements such as pericentric inversions. Interspecific hybrids produced meiotic cells with many abnormalities including desynapsis and heteromorphic bivalents. This analysis revealed new cytological information and involved a hybrid cross between two groups of Collinsia species which had previously produced no fertile hybrids.
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  • Vijay Goyal, Ambuja Pillai
    1986 Volume 51 Issue 4 Pages 637-644
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Changes in structure and zonation occur in the shoot apical meristem of Nico-tiana tabacum Linn. during development from the mature embryo to the repro-ductive phase. The amounts of DNA, RNA and total proteins were quantified and related to the above changes. The plumular apex showed an almost uniform dis-tribution of DNA, RNA and total proteins. DNA and RNA increased during the vegetative and reproductive growth whereas proteins decreased during the vegetative period followed by increase in the reproductive stage. In the vegetative apex the distribution pattern of DNA, RNA and total proteins followed the cytohistological zonation with the peripheral zone (PZ) showing higher content per unit area. In the floret apex the axial located cells showed less DNA, RNA and total proteins till carpel initiation. The entire apex seems to be involved in the reorganisation during transition to flowering.
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  • N. Devadas, Manchikatla V. Rajam, K. Subhash
    1986 Volume 51 Issue 4 Pages 645-653
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    A study has been made of the effects of four organophosphorous insecticides: TARA 909, DDVP, phosphomidon (PMN) and monocrotophos (MCP) on ger-mination, survival and meiotic behaviour in Capsicum annuum. Soaked (24 h) seeds were treated with 0.1, 0.5 and 1.0% of the insecticides for 24h. There was a sig-nificant decline in germination and seedling survival percentage in all insecticidal treatments. All the insecticides were capable of inducing various types of meiotic alterations. Abnormalities consisted of univalents, multivalents, bridges, lagging chromosomes, non-synchronization, multipolar formation, micronuclei, unoriented and unequal disjunction of chromosomes at various divisional stages of PMCs. Stickiness and clumping of chromosomes was a common effect. As a result of these abnormalities, the tetrad formation were highly irregular and caused a high pollen sterility. Chromosomal aberrations and pollen sterility were dose-dependent and there was an apparent relationship between frequency of chromosomal damage and pollen sterility. Among the four insecticides, DDVP and TARA produced greater damage on chromosomes, which also caused significant reduction in ger-mination, survival and pollen viability followed by PMN and MCP.
    The present study has shown that the insecticides were effective mutagenic agents with radiomimetic action, and point out the need of adequate information concerning plant responses to agricultural chemicals to ensure their safe use.
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  • A. Souvré, L. Albertini, A. C. Dhar
    1986 Volume 51 Issue 4 Pages 655-663
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Radioautographic study of 3H-Proline and 14C-Hydroxyproline incorporation into the proteins of microsporocytes, tapetum and connctive of Rhoeo discolor Hance. Cold action on the proteic labelling.
    The incorporation patterns of 3H-Proline and 14C-Hydroxyproline into the nuclear, cytoplasmic and wall proteins of microsporocytes, tapetum and connective of anther during microsporogenesis have been studied in Rhoeo discolor Hance, a plant sensitive to chilling stress. The effect of cold (4°C) on the level of the labelling was also studied.
    The cold treatment was applied to the excised inflorescences either during or after labelling whereas the controls were labelled at 22°C.
    The 3H-Proline incorporation into the nucleus, nucleolus and cytoplasm of the microsporocytes and tapetum and into the connective cell walls were markedly re-duced when the inflorescences where treated by cold during the radioprecursor supply (when compared to the controls, the labelling was generally reduced from 70 to 90%). A strong reduction of the labelling has been observed in the microsporocytes, tapetum and connective cell walls when the cold treatment was applied after the radiopre-cursor incorporations (3H-Proline, 14C-Hydroxyproline): it seems that a proteolysis could induce this reduction especially in the connective cell walls of which the labelling was generally decreased of 80% at minimum. The results are discussed in the light of the datas given in bibliography.
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  • A. S. Khalatkar, Y. R. Bhargava
    1986 Volume 51 Issue 4 Pages 665-669
    Published: December 25, 1986
    Released: March 19, 2009
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    Although light is an important constituent of environment, it has not being taken into consideration by mutation breeders while applying mutagenic treatments. Hence, in the studies being reported here, the effect of different wave-lengths of visible light on ethyl methane sulfonate (EMS) treatments in barley (Hordeum vulgare L.) was investigated. The visible light wave-lengths falling in the range of 450 to 670 nm were observed to induce mitotic as well as meiotic chromosomal aberrations, besides modifying the effectiveness of EMS in the M, generation. The wave-lengths were also found to enhance and broaden the EMS induced mutation frequencies in the M2 generation. Further, these light conditions also broadened the mutation spectrum or eliminated certain types of chlorophyll-deficient mutations. From the data, it may be seen that visible light influence the EMS induced muta-genicity.
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  • Jia F. Chen, Yue J. Lin
    1986 Volume 51 Issue 4 Pages 671-678
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cyclophosphamide (CP) is an alkylating drug for human and animal tumors, but is also implicated in producing cancers at high dosages. Sprague-Dawley rats on control and special diets were exposed to CP in vivo to study the effects of CP on sister chromatid exchange (SCE) frequency. The various diets differed in their protein contents and the amounts of some essential amino acids. The special diets are considered to be less balanced than the control diet. CP treatment increased the SCE frequency in all diet groups of rats. The higher the CP dosage, the higher the SCE frequency. Those rats on less balanced diets were more susceptible to SCE induction.
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  • Alice K. Vari, J. G. Bhowal
    1986 Volume 51 Issue 4 Pages 679-692
    Published: December 25, 1986
    Released: March 19, 2009
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    The seven primary trisomics of Pennisetum americanum were isolated in the progeny of triploid. Based on their specific morphological features the trisomics were named as Papery, Semidwarf, Narrow long leaf, Rolled, Tiny, Necrotic and Narrow dwarf. Most of the phenotypic characters studied in the trisomics showed a correlated variation. The extra chromosome prensent in the trisomics acted in a specific way affecting the anatomy, physiology and morphology of the trisomic plant resulting in a well defined trisomic phentotype which made them distinct from each other as well as from the disomics. The meiotic behaviour especially the trivalent formation and chiasma frequency showed variation in the trisomics. The presence of an extra chromosome in the trisomics was found to bring about an interchromosomal effect on the formation of chiasma by other chromosomes in the complement. The interrelationships between various meiotic events like trivalent formation, chiasma frequency, anaphase separation, micronuclei formation and pollen fertility in respect of specific extra chromosome have been discussed.
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  • III. Rheum L
    R. N. Gohil, G. M. Rather
    1986 Volume 51 Issue 4 Pages 693-700
    Published: December 25, 1986
    Released: March 19, 2009
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    Meiotic details of two species of Rheum have been studied. R. emodi, a dip-ploid species with 2n=22 chromosomes, an accessory chromosome was observed in most of the pollen mother cells studied. In 27% pollen mother cells this B chro-mosome was observed attached to one of the bivalents by a faintly staining connection. It is the first report of the presence of an accessory chromosome in this genus.
    Meiosis in both R. webbianum, a tetraploid species with 2n=44, and diploid R. emodi was mostly normal. The frequency of mutivalents in R. webbianum was very low, which may probably be due to its amphidiploid nature.
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  • A. Arundhati, J. V. Pantulu
    1986 Volume 51 Issue 4 Pages 701-705
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    A derived B chromosome which is telocentric and entirely heterochromatic was obtained upto irradiation of dry seed of Pennisetum typhoides diploid stock. Un-like the other B's reported earlier in this species, this short B is numerically stable. Only one B is present in a plant, it is constant in root tip cells and pollen mother cells. In plants with this derivative B the mean A chromosome chiasma frequency was observed to be lower when compared to sib plants without the B; also the pro-portion of non-distal chiasmata has increased in PMC's with the B. The transmis-sion frequency was low as the B was recovered in 8 to 10 percent of the progeny.
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  • Fernande B. Genest, Pierre Morisset, Robert P. Patenaude
    1986 Volume 51 Issue 4 Pages 707-716
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Le caryotype de ratons laveurs (Procyon lotor Linné) des deux sexes, provenant du Jardin Zoologique de Québec, a été étudié, Des cultures fibroblastiques et lymphocytaires ont permis d'établir des caryotypes conventionnels, en bandes C et en bandes G. Le nombre diploïde est de 2n=38 chromosomes, dont 32 méta-submétacentriques et 4 acrocentriques. Le chromosome X est submétacentrique et l'Y, acrocentrique. Une paire de marqueurs aux satellites proéminents a aussi été observée. En bandes C, it y a peu de coloration au niveau centrometrique, mais un marquage assez fréquent le long des chromatides de certains chromosomes. Les techniques des bandes C et G ont permis d'identifier et de décrire certains chro-mosomes de façon précise et de présenter un carytype complet différent de celui proposé par les auteurs antérieurs. Quelques similarités et différences entre le caryotype du Raton laveur et celui du Panda géant sont signalées.
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  • O. Aniel Kumar, Ramesh C. Panda, K. G. Raja Rao
    1986 Volume 51 Issue 4 Pages 717-721
    Published: December 25, 1986
    Released: March 19, 2009
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    After gamma irradiation (30 Kr) of seeds of Capsicum annuum cultivar cerasiformis (2n=24) two plants were recorded each carrying two interchanges. The nucleolus organiser chromosome appeared not to be involved. The interchange heterozygotes were weak and meiosis was irregular. At least one multivalent as-sociation per PMC was recorded. At metaphase I the predominant orientation was adjacent. The probable reasons for anaphase I and other meiotic irregularities and the incidence of high pollen sterility are discussed.
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  • IV. Trachelomonas Ehrenberg emend. Deflandre
    B. R. Chaudhary, R. N. Prasad
    1986 Volume 51 Issue 4 Pages 723-729
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    In spite of the abundance and world-wide distribution of euglenoid genera, our knowledge on the nuclear cytology of Euglenineae is very scanty. Further, as far as the Indian subcontinent is concerned, no one appears to have done any karyo-logical work on this fascinating group of algae, excepting Sarma and Shashikala (1980) who investigated the karyology of three species of Euglena and Chaudhary and Prasad (1983, 1985) and Prasad and Chaudhary (1984) who studied the cytology of four taxa of Phacus and five of Strombomonas and one taxon of Astasia, respe-ctively. In the genus Trachelomonas, only two species viz., T. grandis (n=44-60) and T. bulla (n=75) are reported to have been studied karyologically so far (Leedale 1966).
    In view of the paucity of informations and peculiar mitosis eight species of Trachelomonas collected from freshwater habitats in and around Varanasi were in-vestigated karyologically in the present course of study and their nuclear features are being reported here for the first time. The chromosome numbers, all being estimates owing to inherent difficulties, ranged from n=20±1 in T. punctata to n=96±5 in T. dybowskii and are new to science. The structure and pattern of division of nuclei met with in these euglenoid flagellates do not conform to those of typical eukaryotic algae.
    From a perusal of chromosome numbers, though based on few counts it can be stated that both aneuploid and euploid have played decisive role in speciation and evolution of the genus Trachelomonas.
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  • R. C. Verma, A. Sarkar, B. C. Das
    1986 Volume 51 Issue 4 Pages 731-736
    Published: December 25, 1986
    Released: March 19, 2009
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    Cytomixis was observed in triploid mulberry. The cause of this has been attributed to initial hybrid nature of tetraploid and triploid. The cytomixis involved many cells at a time and was observed in all the stages of meiosis, contrary to the common belief that only earlier stages are favourble. In some cases two different stages of meiosis were also involved in cytomixis. Cytomixis resulted in other abnormalities like anucleate cells, cells with more or less chromosome number, multinucleolate cells, unusually large cells, triads, pentads and hexads. Cytomixis leads to sterility in mulberry resulting in higher leaf yield and nutritiveness, useful for silkworm feeding.
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  • G. V. Subrahmanyam, T. N. Khoshoo
    1986 Volume 51 Issue 4 Pages 737-748
    Published: December 25, 1986
    Released: March 19, 2009
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    The present studies are based on three species of the genus Costus viz., C. speciosus Sm., C. malortieanus H. Wendel and C. megalobractea K. Schum. C. spe-ciosus contains intraspecific chromosomal races namely diploid (2n=18), triploid (2n=27) and tetraploid (2n=36). This taxon has been studied in cytogeographic angle, and it is clear that the materials originating from different geographic regions of India have different ploidy levels. Intraspecific triploid hybrids (2n=27) were obtained by crossing natural tertaploid and diploid C. speciosus. The chromosome number recorded for the species C. megalobractea (2n=36) in the present studies is the first report on the taxon. The detailed karyotype analyses were made in all these taxa, while the meiotic analyses were carried out on the diploid and tetraploid cytotypes of C. speciosus. On the basis of the present cytological data, it can be concluded that polyploidy and structural changes of the chromosomes have played and important role in the evolution of the genus Costus.
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  • Eduardo Angulo, Jesús Moya
    1986 Volume 51 Issue 4 Pages 749-752
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    La membrane basale de I'épithélium du sac rénal des limaces Arion ater et A. intermedius revèle au microscope électronique une infrastructure de barres paralel-les très serrées en quinconce. Ces barres, mésurant 15-20 nm en diamètre, ont une séparation de 20-30 nm.
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  • K. J. Madhusoodanan, M. A. Nazeer
    1986 Volume 51 Issue 4 Pages 753-756
    Published: December 25, 1986
    Released: March 19, 2009
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    Successful intercrossing has been carried out between a ‘Soudanien’ and a ‘Guineen’ type of okra, of which the latter is reported to be immune to the yellow vein mosaic (YVM) virus disease. However, due to difference in chromosome numbers of the parents the hybrid exhibited abnormal meiosis leading to sterility and thereby hinders fruitful incrorporation of the disease resistant gene to the former. Phylogenetic relationship between them is discussed. Origin of ‘Guineen’ type through natural hybridization between A. esculentsus and A. manihot is suggested.
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  • A. Ganapathi, G. R. Rao
    1986 Volume 51 Issue 4 Pages 757-762
    Published: December 25, 1986
    Released: March 19, 2009
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    Several reciprocal cross pollinations were made between Solanum nigrum (2n=72) and S. retroflexum (2n=48); crosses were successful when the higher chromo-somal form was used as female parents; the cause for failure of its reciprocal crosses was discussed.
    Cytomorphological features of the species and their F1 hybrid were studied. The hybrid was pentaploid (2n=60). Its breakdown of meiosis and high pollen sterility seem to be primarily due to chromosomal cause. From the occurrence of as many as 24 bivalents and 12 univalents in few pollen mother cells of the hybrids, it is suspected that S. retroflexum or one of its close relatives has participated in origin of S. nigrum.
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  • Yutaka Yamazaki
    1986 Volume 51 Issue 4 Pages 763-765
    Published: December 25, 1986
    Released: March 19, 2009
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    Young adventitious roots of Gibasis geniculata were cultured with some chemical agents dissolved in water to examine the cellular polarity with respect to root hair formation. As a result, 10-4 M colchicine, 10-5 M cytochalasin B, 10-4 M mor-phactin, and 10-3 M TIBA were specially effective for disturbing polarity.
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  • B. G. Sangowawa, H. C. Choudhuri
    1986 Volume 51 Issue 4 Pages 767-776
    Published: December 25, 1986
    Released: March 19, 2009
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    The haploid number of chromosomes in S. polytrichon Rydb. is found to be 24 (n=24) and is therefore tetraploid, since the basic number of chromosomes in potato is n=12. Frequencies of chiasmata at diplotene and diakinesis are analysed. The chiasma frequency per bivalent at diplotene and diakinesis varied from 1.62 to 1.22 respectively.
    The incidence of quadrivalents in the tetraploid species investigated is high 44.33%. This gives indication that they are autotetraploid and therefore shows a high degree of affinity between four sets of chromosomes.
    The percentage of univalents is 21.62. Mechanical interference with pairing owing to presence of four sets of homologous chromosomes is likely to cause more failure of pairing in tetraploids. It is also probably that genetic dissimilarity of individual chromosomes is also responsible for certain amount of failure of pairing amongst pairable chromosome mates in Solanum. The univalents behave in dif-ferent ways; they either pass to the poles or lag in between separating groups of chromosomes or divide. The division and elimination of univalents cause unequal distribution of chromosomes on second metaphase plates. Univalents and fragments which failed to be included in the daughter nuclei formed micronuclei (44.06%).
    The frequency of chromatid bridge is 3.94. There is no relationship between the chromatid bridge and deformity of pollen in S. polytrichon. The abortion of pollen grains in this species is presumably due to gene mutation.
    The strong homology between four genomes indicates that it is probably of autopolyploid origin. It can therefore be suggested that one of the main lines of evolution is the tetraploid S. polytrichon Rydb. has been the occurrence of polyploidy.
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  • M. Z. Haque, M. B. E. Godward
    1986 Volume 51 Issue 4 Pages 777-784
    Published: December 25, 1986
    Released: March 19, 2009
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    In the M1 plants from seed irrdaiated Lactuceae, at least two types of chlorophyll mutant, “albo-xantha a” common to two cultivars of L. sativa, and “albo-xantha b” common to L. sativa and L. serriola, were recognised (c.f. von Wettstein et al. 1971, von Wettstein 1980). They are illustrated and discussed.
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  • Michèle Ferrand, Eliane Chenou, Janine Kuligowski
    1986 Volume 51 Issue 4 Pages 785-792
    Published: December 25, 1986
    Released: March 19, 2009
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    Les désordres ultrastructuraux consécutifs à la sénescence du gamète femelle du Marsilea vestita ou à un traitement physique (abaissement de la température) ou chimique (présence de colchicine dans le milieu de culture) sont accompagnés de l'apparition d'éléments du cytosquelette: des faisceaux de filaments, jamais ob-servés jusqu'alors. Ces derniers proches des chloroplastes et des mitochondries, pourraient être impliqués dans des phénomènes de flux cytoplasmique liés à un êtat physiologique de stress de la cellule fertile femelle.
    Mots clés: cytosquelette, filaments, ultrastructure, gamète femelle, sénescence.
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  • R. R. Hegde, C. K. Rudramuniyappa
    1986 Volume 51 Issue 4 Pages 793-801
    Published: December 25, 1986
    Released: March 19, 2009
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    Total polysaccharides, RNA and proteins were localized cytochemically in the developing pollinium of Calanthe masuca (Orchidaceae). The sporogenous cells show thin PAS-positive cell walls and high contents of RNA and proteins to begin with and later PAS-positive granules accumulate in them. In the meiocytes, the PAS-positive granules disappear and RNA and protein contents decline. Following meiosis, the microspores do not separate from the tetrad. The microspores syn-thesize PAS-positive granules, RNA and proteins. The thick cell wall material around the meiocytes and tetrads reacts red purple with PAS and toluidine blue. The tapetum possesses high RNA and proteins, but does not store polysaccharides. Significantly from the tapetum, toluidine blue-positive green material extrudes and accumulate around the pollinium to begin with, and later, on the periphery of the microspores. As a consequence, the microspore wall develops green tinge with toluidine blue. The anther wall layers store abundant PAS-positive granules, RNA and proteins. The endothecial thickenings react red-purple, green and blue with PAS, toluidine blue and amido black lOB tests, respectively.
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  • I. General Karyomorphological Characteristics of the Genus
    Siro Kurita
    1986 Volume 51 Issue 4 Pages 803-815
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The general karyomorphological characteristics of fifteen taxa of Lycoris have been studied and the results are itemized as follows.
    1) The resting nuclei of all examined taxa are diffused type.
    2) Three fundamental types of chromosome are recognized; i.e. large metacentrics (M type), telocentrics (T type) having heterochromatic block at the proximal region, and acrocentric chromosomes (A type). Other types such as M', T', a and m are produced from three fundamental types by various structural changes. Details will be reported in the forthcoming papers.
    3) C-banding pattern and pairing behaviour in each of the fundamental types of chromosome suggest that they have partial homology with one another.
    4) The quantity and position of C-banding positive constitutive heterochromatin in M and T type chromosomes of the genome of L. traubii is remarkably similar to those of Nothscordum fragrans, Allioideae.
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  • Jacques Cayouette, Pierre Morisset
    1986 Volume 51 Issue 4 Pages 817-856
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Dans le nord-est de l'Amérique du Nord, le complexe du Carex salina s. l. com-prend trois espèces croissant dans les marais salés boréaux on arctiques: C. subspa-vaavql Wormsk., C. salina Wahl. s. str. et C. recta Boott. Les auteurs ont étudié les chromosomes (nombres et comportement méiotique) de plantes provenant de la vallée du Saint-Laurent, de la baie d'Hudson et du détroit d'Hudson. Les 14 individus de C. subspathacea forment une série anuploïde de 2n=78, 80, 81, 82, 83, avec 2n=81 comme nombre nouveau pour cette espèce, et 2n=80 et 82 comme seuls cytotypes parfaitement euploïdes. Chez 22 individus de C. sauna (2n=77, 78, 79) et 25 de C. recta (2n=73, 75, 76) aucun des cytotypes n'est parfaitement euploïde. Les trois nombres du C. sauna sont nouveaux ainsi que 2n=76 pour C. recta. La forte fréquence de trivalents hétéromorphes semble indiquer que l'aneuploïdie de ces plantes serait surtout causee par fission et/ou fusion de chromosomes (agamtoploïdie). En vue de comparer plus adequatement les individus aneuploïdes entre eux (ainsi que les cytotypes et les espèces), une formule indiquant l'affinité maximale d'appariement a été élaborée ainsi que deux indices d'euploïdie. Ces données ont permis de déterminer que les cytotypes aneuploides de C. subspathacea (2n=78, 81, 83) et celui à 2n=73 de C. recta sont les moins perturbés de tous. L'origine des différents cytotypes est discutée. Un cas de non-réduction est signalé chez C. recta.
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  • Jacques Cayouette, Pierre Morisset
    1986 Volume 51 Issue 4 Pages 857-883
    Published: December 25, 1986
    Released: March 19, 2009
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    Dans le nord-est de l'Amérique du Nord, Carex paleacea, C. nigra et C. aquatilis croissent fréquemment dans les marais salés quoique les deux dernières espèces peuvent se retrouver dans d'autres types d'habitats. Les auteurs ont étudié les chro-mosomes (nombres et comportement méiotique) de plantes provenant de la vallée du Saint-Laurent, du Nouveau-Québec et de lîle Cornwallis, dans l'Arctique cana-dien. Les 16 individus du C. paleacea et les 7 du C. nigra forment deux courtes séries aneuploïdes, respectivement de 2n=ca. 71, 72, 73, et de 2n=83, 84, 85. Toutes les deux sont composées d'un cytotype parfaitement euploïde encadré d'un cytotype hypoploïde et d'un autre hyperploïde. Chez 13 individus du C. aquatilis, la série aneuploïde comprend des nombres consécutifs de 2n=74 à 2n=80. Trois de ces nombres sont nouveaux pour C. aquatilis, soit 2n=75, 78 et 79, Seulement deux des cytotypes du C. aquatilis (2n=74 et 78) soot parfaitement euploïdes; les autres présentent différents types d'irrégularités méiotiques. La présence de trivalents homomorphes et hétéromorphes semble indiquer que l'aneuploïdie de ces plantes pourrait avoir différentes causes, trisomie et fission ou fusion de chromosomes. En vue de comparer plus adéquatement les individus aneuploïdes entre eux, une formule indiquant l'aflinité maximale d'appariement a été élaborée ainsi que deux indices d'euploidie. Les deux individus aneuploïdes du C. aquatilis ssp. stans de lîle Corn-wallis à 2n=76, sont les plus perturbés de tous. La présence de microspores non réduites est signalée chez un autre cytotype du C. aquatilis.
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  • Golam Kabir, Sultanul Alam
    1986 Volume 51 Issue 4 Pages 885-892
    Published: December 25, 1986
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • C. K. John, S. H. Tulpule, R. J. Thengane
    1986 Volume 51 Issue 4 Pages 893-898
    Published: December 25, 1986
    Released: March 19, 2009
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    In the genus Alysicarpus karyotypic details were studied in seven species. In A. bupleurifolius DC., A. hamosus Edgew., A. pubescens Law., A. rugosus DC., A. tetra-gonolobus Edgew. and A. vaginalis DC. the chromosome numbers were found to be 2n=16. A. belgaumensis Wight. is the only species with chromosome number 2n=22. For A. belgaumensis Wight. (2n=22) and for A. pubescens Law. (2n=16) are new reports. The total chromosome length varied from 77.44μm (A. belgaumensis Wight.) to 43.24, μm (A. buplerifolius DC.). The TF percentage varied from 46.17 (A. hamosus Edgew.) to 37.58 (A. tetragonolobus Edgew.).
    When classified according to Stebbins' two-way system of classification of karyotype asymmetry A. hamosus Edgew. belongs to 1 A and A. pubescens Law. belongs to 2A, the remaining five species belong to 2B. As only three classes were represented in the seven species analysed the karyotype asymmetry appears to be of a lower degree.
    It was seen that, for the length of individual chromosome pairs the correlation coefficients were higher pointing towards close relationships. However, the coefficients of correlation for arm ratios being very low, reveal the possible mode of diversification due to structural alterations like inversions and translocations bring-ing about changes in the arm ratios.
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  • 1986 Volume 51 Issue 4 Pages e1
    Published: 1986
    Released: March 19, 2009
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