CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 45 , Issue 1-2
Showing 1-36 articles out of 36 articles from the selected issue
  • A. P. Singh
    1980 Volume 45 Issue 1-2 Pages 1-31
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The very young sieve elements are characterized by a thin wall, relatively dense cytoplasm, and plastids with the characteristics of proplastids. Among the most pronounced changes accompanying early and mid phases of sieve element differentiation are: 1) acquisition of electron dense, proteinaceous inclusions by the plastids, 2) an increase in the size of plastids and their proteinaceous inclusions, 3) an increase in wall thickness, and 4) development of sieve plates and pore sites. In advanced stages of their differentiation, sieve elements are subjected to the action of a variety of enzymes, many of which function in hydrolyzing various protoplasmic components. At maturity, sieve elements lose nuclei, most of the ER, ribosomes, dictyosomes, microtubules, and tonoplasts. The companion and parenchymatic cells undergo little changes as compared with their adjoining sieve elements. As judged by their nuclear and cytoplasmic condition, companion cells are metabolically active throughout their life. Plasmodesmata are present among sieve elements, companion cells and parenchymatic cells throughout their development and at the maturity of these elements.
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  • Hisakazu Ogura
    1980 Volume 45 Issue 1-2 Pages 33-42
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytogenetical and morphological reexaminations of a recently identified Nicotiana species, N. kawakamii Ohashi were conducted, and Ohashi's observation (1976) was confirmed. Comparison of its karyotypes and morphological characteristics with those of the related species in the section Tomentosae indicated that N. kawakamii is most resembled to N. tomentosa. In the meta-anaphase I, F1s of both N. kawakamii×N. tomentosiformis and N. kawakamii×N. otophora showed 12 bivalent chromosomes in a majority of their PMCs, indicating that N. kawakamii is closely related to the three known T-genome analyzers of the section Tomentosae, i.e., N. tomentosiformis, N. otophora and N. tomentosa. The average number of bivalents in meta-anaphase I of PMCs and pollen fertility were a little higher in (N. sylvestris×N. kawakamii) F1 than in (N. sylvestris×N. tomentosiformis) F1, however, the difference was not significant.
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  • Dértia V. Freire-Maia, Margery W. Shaw, Marjorie Hendrickson, A ...
    1980 Volume 45 Issue 1-2 Pages 43-48
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cell changes were studied in short term cultures of circulating lymphocytes from eight cancer patients undergoing surgery with general anesthesia. Two blood samples were drawn from each patient, one immediately before and one after surgery. Over 8, 500 and 7, 600 cells were counted in the pre and postsurgery samples, respectively. It is found that, after surgery, both mitotic rate and incorporation of tritiated thymidine may be decreased, and that this decrease may have resulted from the effect of anesthetics, although a trauma of surgery effect cannot be ruled out. No apparent chromosomal damage occurred in the patients studied.
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  • Rozalia Vintilå, M. Keul
    1980 Volume 45 Issue 1-2 Pages 49-55
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    DL-Äthionin (10-2-10-6M) bewirkt mit steigender Konzentration and Verlängerung der Behandlungsdauer eine fortschreitende Hemmung der Protoplasmaströmung in den Wurzelhaaren der Gerste (Hordeum vulgare L.). Die DL-Äthioninwirkung (10-2M) kann durch Adenosin (10-2M), nicht aber durch DL-Methionin (10-2M) aufgehoben werden. Die Vorbehandlung and gleichzeitige Verabreichung mit DL-Methionin setzt die DL-Äthioninwirkung herab. Die Hemmwirkung von DL-Äthionin auf die Plasmaströmung wird durch den Eingriff in den Energiestoffwechsel erklärt. Aufgrund der erzielten Ergebnisse wird die Anwendung von DL-Äthionin bei der Untersuchung der Energieabhängigkeit der Plasmamotilität empfohlen.
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  • II. Mitotic effect of water extract of Teucrium pilosum on Allium cepa
    A. S. Shehab
    1980 Volume 45 Issue 1-2 Pages 57-64
    Published: June 25, 1980
    Released: March 19, 2009
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    The effect of water extract from Teucrium pilosum on mitoisis of Allium cepa was studied.
    The extract had anti-mitotic effect on Allium cepa roots. Accumulation of prophases on the expense of the other phases was clear after direct treatment. While they nearly regain their normal percentage after 24h recovery.
    The induced types of abnormalities were, spindle disturbance, stickiness, C-mitosis, lagging (or surpassing) chromosome, bridges, polyploidy and breaks.
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  • Usha Bhat née Dhar, M. R. Vijayaraghavan
    1980 Volume 45 Issue 1-2 Pages 65-75
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Distribution of insoluble polysaccharides has been studied in various parts of the seed, in Linum usitatissimum Linn., during embryogenesis and germination. PAS-positive grains are localized in the endothelial cells at about octant proembryo stage. In endosperm, concentration of polysaccharides increases during embryogeny. The egg and the zygote show perinuclear arrangement of starch grains. In globular proembryo, large number of polysaccharide grains are localized in the hypophysis. In a dry seed, no PAS-positive grains are observed in either the cells of endosperm or the embryo. Starch begins to accumulate after germination.
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  • H. K. Goswami, Sharda Khandelwal
    1980 Volume 45 Issue 1-2 Pages 77-86
    Published: June 25, 1980
    Released: March 19, 2009
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    Followings are other important observations:
    1. Occurrence of supernumerary chromosomes of very small size (1.4μ); i.e. microchromosomes are recorded in O. nudicaule, O. gramineum, O. sp. and O. thermale.
    2. A peculiar phenomenon of linear attachment of bivalents i.e., interchromosomal connections is observed for the first time in Ophioglossum.
    3. Plants of O. thermale growing intermixed with O. sp. are characterised by ca. 360 bivalents, which is a new count for the species.
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  • Seiichi Sato, Shigeki Ohta, Yûzô Kuroki
    1980 Volume 45 Issue 1-2 Pages 87-96
    Published: June 25, 1980
    Released: March 19, 2009
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    The nucleolus organizer regions were studied in Nothoscordum fragrans, Liliaceae (2n=19) applying the technique of C-banding. This technique allowed us to distinguish the six acrocentric chromosomes into four types by the banding patterns in the long arms and also to observe in detail the nucleolus organizer regions and nucleoli. The distal ends of the short arms of all six acrocentric chromosomes had a characteristic appearance at metaphase: completely condensing, fluff-like diffusing or amorphous loosening of the chromatin. These three characteristic formations seemed to represent a progressive alteration of the morphology of the short arms during metaphase. These regions were confirmed to be the nucleolus organizer regions since they were attached to the nucleoli at prophase. The frequencies of the three characteristic formations were studied for each type chromosome. There was a quantitative difference in the diffused or loosened chromatin for each type of chromosome. The possibility that this may reflect the size of the nucleolus organizer regions is discussed.
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  • Kohji Karasawa, Ryuso Tanaka
    1980 Volume 45 Issue 1-2 Pages 97-102
    Published: June 25, 1980
    Released: March 19, 2009
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    1. C-banding pattern of 2n=32 chromosomes of P. callosum was found to correspond with that of 2n=26 chromosomes of P. insigne var. sanderae, when the one-armed chromosomes of the former were arranged in the shape of two armed chromosome.
    2. No structural heterozygosity was observed in the chromosomes of P. callosum.
    3. The results of C-banding analysis are a further confirmation of the centric fission hypothesis on the increase of chromosome number in Paphiopedilum.
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  • K. T. Ramavarma, K. Apparao, S. Sitharamaiah, A. I. Narayanan
    1980 Volume 45 Issue 1-2 Pages 103-111
    Published: June 25, 1980
    Released: March 19, 2009
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    In tobacco (Nicotiana tabacum L.), there is a very little scope for intervarietal gene transfer, hence interspecific hybridization utilising wild species of the genus Nicotiana possessing resistance to one or more pests, is the best solution. Eventhough N. benthamiana is resistant to tobacco caterpillar (Spodoptera litura F.), in view of its interspecific incompatibility with N. tabacum, a trispecific amphiploid (N. benthamiana×N. glutinosa×N. tabacum) was synthesised with N. glutinosa as a bridge species. Progressive elimination of N. benthamiana and N. glutinosa chromosomes was achieved through four successive back-crosses of the amphiploid with flue-cured N. tabacum varieties, resulting in plants having most of the tabacum characters and caterpillar resistance. All the plants were male-sterile and most of them possessed 48-50 mitotic chromosomes, 48 from N. tabacum and 1-2 from N. bentamiana thus indicating that the resistance factors are confined to one or two chromosomes. Based on the mortality of inoculated larvae and the extent of damage, the plants were grouped into highly resistant, moderately resistant and susceptible types.
    The heavy mortality of the caterpillar within 24 hours indicate that certain toxic exudates from the leaf surface may be the primary cause of death. Starvation due to “non-preference” may be another factor responsible for death of most of the remaining larvae within the next 24-240 hours. The retarded growth of a few surviving larvae, their resistant feeding and the slow pace at which they proceed from one instar to another indicate that some “antibiosis” properties may also be associated with the factors for resistance.
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  • Robert R. Wise, Joseph B. Harris
    1980 Volume 45 Issue 1-2 Pages 113-126
    Published: June 25, 1980
    Released: March 19, 2009
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    Using the techniques of fractional centrifugation, light and electron microscopy, unique features of the chloroplasts of Callisia fragrans (Linda.) Woods were observed. In size, shape, and in their different stages of development, these chloroplasts were comparable to those described for Lycopersicon, Pelargonium, and Cyhomandra. Callisia chloroplasts differ from others in sedimentation properties and in the relatively high volume of the chloroplast occupied by the thylakoid system. There was almost no stroma. All Callisia chloroplasts were sedimented by a force of 1000g. There were very few fragments. Starch-associated stroma was highly granular and dense in most cases. Plastosomes were not numerous, yet showed unique relationships with thylakoids. Plastoglobuli were observed.
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  • J. Moutschen, M. Moutschen-Dahmen
    1980 Volume 45 Issue 1-2 Pages 137-148
    Published: June 25, 1980
    Released: March 19, 2009
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    The uptake of H3-uridine was investigated in two lines of Chara: a “nitellised” (without cortical cells and sex organs) and a normally corticated. Differences were noted between the activity of both lines in the successive segments from the apex, and independently in the branchlets of the whorls and in the internodes.
    In corticated samples, RNA turn-over was followed in antheridia during the last division of spermatogenesis and in oogonia at various stages of development. AMD exposures were found to inhibit RNA synthesis more drastically in “nitellised” than in corticated samples, but much less in oogonia. These findings were correlated with cytological observations, which revealed a higher sensitivity of internodal nuclei in which nucleoli progressively disappear and the nuclear segmentation at the end of amitosis cannot be achieved. Some phenomena described can be related to the occurrence of specific gene amplification processes in Chara cells.
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  • E. W. Rajasekhar, S. Chatterjee, Susan Eapen
    1980 Volume 45 Issue 1-2 Pages 149-155
    Published: June 25, 1980
    Released: March 19, 2009
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    Interkingdom fusion of amoeba cells with belladonna and mung bean protoplasts was accomplished with the use of polyethylene glycol. Heterocellular adhesion and subsequent formation of heterokaryons has been followed with light microscopy and confirmed by autoradiography. The fusion frequency, though varied, was as high as 85% in some experiments. The plant nuclei divided repeatedly within the alien cytoplasm of amoeba. No synchrony in nuclear divisions could be detected but aberrations were observed that led to the formation of micronuclei and the latter increased numerically on prolonged culture.
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  • A. B. Schooler, M. K. Anderson
    1980 Volume 45 Issue 1-2 Pages 157-162
    Published: June 25, 1980
    Released: March 19, 2009
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    Partially fertile F1 plants were obtained from crosses between synthetic autotetraploid Hordeum vulgare L. (2n=28) and a tetraploid Elymus mollis L. type (2n=28). The F1 plants were about the same size as the barley parent. Spikelets were sometimes altered in arrangement on the rachis, but in general more closely resembled the barley parent than Elymus. The seeds on the selfed F1 spikes were larger and more shriveled than those of autotetraploid barley.
    Elymus and Hordeum chromosomes could not be distinguished in most of the meiotic cells examined in the tetraploid and triploid hybrids. However, chromosomes of the Elymus parent appeared to be slightly smaller than chromosomes of the barley parent. At least eight of the 14 Hordeum chromosomes paired with eight from Elymus in the tetraploid hybrid (2n=28) and both auto and allo-syndetic pairing were observed. Cytological examinations of microsporocytes from triploid plants (2n=21) obtained from crosses of the tetraploid hybrid (2n=28)×H. vulgare L. (2n=14) showed similar types of chromosome pairing as observed in the tetraploid hybrid.
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  • I. Mitotic effects of Vitavax-200 and Dithane S-60 on wheat and two related species
    Nahla R. Al-Najjar, Atef S. Soliman
    1980 Volume 45 Issue 1-2 Pages 163-168
    Published: June 25, 1980
    Released: March 19, 2009
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    Two commonly used fungicides Vitavax-200 and Dithane S-60 which are used to control many pathogenic fungi affecting wheat were applied to pure seeds of the species T. aestivum, T. durum and Ae. ligustica with the rate of 2gm/Kg of seeds. The fungicides caused highly significant reduction in mitotic index, significant increase in relative duration of metaphase stage, and high percentage of chromosomal aberrations mainly chromosomal bridges during anaphase stage. The aberrations induced by the fungicides Vitavax and Dithane are similar to aberrations induced by other pesticides, chemical mutagens and radiations. There was no correlation between the level of ploidy and the mitotic effects caused by the two fungicides.
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  • II. Chromosomal aberrations induced by Vitavax-200 and Dithane S-60 in meiotic cells of wheat and two related species
    Atef S. Soliman, Nahla R. Al-Najjar
    1980 Volume 45 Issue 1-2 Pages 169-175
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The meiotic effects of Vitavax-200 and Dithane S-60 on hexaploid wheat T. aestivum, tetraploid wheat T. durum and diploid related species Ae. ligustica. The treatment with the above fungicides caused a highly significant increase in the number of abnormal cells in different percentages. The kinds of abnormalities observed were lagging chromosomes, single bridges, multiple bridges, ring chromosomes and asynchronization within single cells. Chromosome stickinass observed might be the cause of the above abnormalities. It was concluded that Vitavax and Dithane are similar in their action to chemical mutagens. Moreover the increase in ploidy level was accompanied by the increase in number of abnormal cells.
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  • A. Chakrabarti, J. Roychowdhury
    1980 Volume 45 Issue 1-2 Pages 177-184
    Published: June 25, 1980
    Released: March 19, 2009
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    Chromosome analysis of an ascitic form of mouse sarcoma 180 has been made both by conventional Giemsa staining as well as by C-banding. The modal number has been found as 75 with one biarmed marker in the present ascitic tumour. C-banding analysis reveals that this submetacentric marker is actually a dicentric chromosome with two closely situated C-positive heterochromatic zones. In addition to this marker, the cell line also possesses another stable and transmissible dicentric chromosome with two distinctly terminal centromeres, and an another unusual chromosome with an extended centromeric heterochromatin.
    Spontaneous chromosome elimination during anaphase separation, endoreduplication, multipolar spindle formation, etc. have been recorded in a high frequency which are assumed to be responsible for the characteristic ploidal variation in this cell line.
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  • A. P. Singh, M. Greer
    1980 Volume 45 Issue 1-2 Pages 185-188
    Published: June 25, 1980
    Released: March 19, 2009
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    Conspicuous deposits of phytoferritin were regularly noted within the plastids of subepidermal cortical cells in nicotine treated alfalfa root tips. Plastids of the control material generally lacked phytoferritin deposits.
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  • Omotoye Olorode, J. A. Morakinyo
    1980 Volume 45 Issue 1-2 Pages 189-196
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
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  • Panuganti N. Rao, N. K. Rao
    1980 Volume 45 Issue 1-2 Pages 197-202
    Published: June 25, 1980
    Released: March 19, 2009
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    In a population of annual chrysanthemum (Chrysanthemum coronarium L., 2n=18), two desynaptics with interchange complexes were located and their meiosis studied. They differed from one another and from the comparable normal synaptic interchange heterozygotes in the average frequency per cell of higher associations, bivalents, univalents and chiasmata. The number of chiasmata and univalents per cell showed a significantly high negative correlation. The intercell distribution of univalents and chiasmata were compared with the Poisson and binomial distribution, and they differed significantly indicating their non-random occurrence. Analysis of variance with reference to intercell and intracell variation in chiasmata revealed that the intercell variance contributed significantly more than intracell variance in causing the deviations from randomness in chiasma and univalent formation. Desynapsis is probably governed by a major factor associated with a number of modifiers exhibiting incomplete penetrance and variable expression.
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  • Maria L. S. Mello, Heloisa H. Raymundo
    1980 Volume 45 Issue 1-2 Pages 203-209
    Published: June 25, 1980
    Released: March 19, 2009
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    When fifth instar nymphae or adults of the reduviid, Panstrongylus megistus, are subjected to a 4.5-month starvation period, nuclear fusion occurs in some of the epithelial cells of their Malpighian tubes. The affected nuclei had previously attained their maximal ploidy degrees by endomitosis. Nuclear fusion was demonstrated visually or with cytophotometric and karyometric procedures. Fusing nuclei pertaining to 64 C, 128 C, and 256 C Feulgen-DNA classes were found in the starved specimens, whereas unfusing nuclei pertaining to 32 C and 64 C classes were detected in normal controls and fasted insects. The doublings on nuclear areas in the fusing nuclei generally agree with those on Feulgen-DNA data. Exceptions showing nuclear sizes exceeding those expected from Feulgen-DNA contents are maybe concerned with an increase in nuclear hydrating levels and/or inclusion of cytoplasmic matter in the nuclei during their fusion.
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  • G. P. Sharma, Usha Nakhasi
    1980 Volume 45 Issue 1-2 Pages 211-219
    Published: June 25, 1980
    Released: March 19, 2009
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    In the family Agamidae, there has been observed a conservativeness for the total number of arms in the karyotype. All the diploid species have twenty-two (Calotes versicolor, Calotes jerdoni, Ptyctolaemus gularis; present report) or twentyfour (Uromastix hardwickii, present report) micro-chromosomes and all but three species have twenty-four macro-chromosomal arms, twelve meta-/submetacentric (group-I) or twenty-four acrocentric chromosomes (group-II). The group-I karyotype has evolved from group-II karyotype through the centric fusions of twelve medium sized acrocentric and twelve large acrocentric elements of the group-II karyotype.
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  • J. L. Tarar, V. R. Dnyansagar
    1980 Volume 45 Issue 1-2 Pages 221-231
    Published: June 25, 1980
    Released: March 19, 2009
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    Meiosis is normal in control plants. As a result of gamma rays or EMS treatment, the plants showed varying degree of meiotic irregularity. This irregularity increased with the higher exposure to gamma rays and higher concentration and duration of EMS treatment. The various types of abnormalities observed in diffrent stages of R1 and M1 generations include stickiness of chromosomes, chromosome fragments, disturbed bivalent associations resulting in multivalent formation, precocious movement, laggards, bridge with or without fragment and formation of micronuclei at meiosis I and II.
    The percentage of PMC's showing meiotic abnormalities was less in plants raised from EMS-treated seeds than that of gamma irradiation.
    Meiotic irregularities were less in the second generation whereas in the third generation they were noticed occasionally.
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  • V. Bhaskar
    1980 Volume 45 Issue 1-2 Pages 233-239
    Published: June 25, 1980
    Released: March 19, 2009
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    In Impatiens of South India, there appears to be greater variation in the chromosome numbers in the scapigerous members than in the non-scapigerous ones. Of the two populations of I. scapiflora var. pseudo-acaulis examined one of them showed chromosomal drift more frequently than the other. In 25 plants scanned from the first group 22 were n=10, one was n=16, one was n=10 and 20, and one was n=20. In the second population 55 plants were scanned, in which only one generative cell in a plant showed n=10+>20. Similarly in I. modesta, one of the three populations studied showed frequently n=8 (22 plants), n=8 and 9 (4 plants), n=9 (3 plants) and n=16 (2 plants). It is also noticed that n=20 in I. scapiflora var. pseudo-acaulis and n=16 in I. modesta are tetraploid numbers which are always associated with 5-6 colpate pollen grains in place of the usual 3-4 colpate pollen grains in those with diploid numbers. This indicates that diploids and polyploids are frequently mixed up in the same population which are not distinguishable morphologically.
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  • X. Meiotic effects of “Phosvel”
    Soheir M. Amer, Odette R. Farah
    1980 Volume 45 Issue 1-2 Pages 241-245
    Published: June 25, 1980
    Released: March 19, 2009
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    The effects of the insecticide O-(4-bromo-2, 5-dichloro-phenyl) O-methyl phenyithiophosphonate “Phosvel” on the meiosis and pollen viability of Vicia faba were studied. The plants were sprayed at the seedling and flowering stages with two concentrations of the insecticidal solution which are usually used in the field in Egypt (2.25 L. of “Phosvel” solution “active ingredient 30%” were mixed with 200 L. water for the first concentration, and with 500 L. water for the second one). Most of the treatments affected a significant percentage of abnormal pollen mother cells. The induced meiotic irregularities were: disturbed 2 nd meta- and anaphases, stickiness, lagging chromosomes, fragments, anaphase bridges, univalents in diakinesis, micronuclei in the 1st and 2 nd telophases tages and multipolar telophase II. “Phosvel” did not show significant effect neither on tetrads nor on pollen viability.
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  • S. P. Bhatnagar, Jose Kallarackal
    1980 Volume 45 Issue 1-2 Pages 247-256
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Qualitative cytochemical localisation of insoluble polysaccharides, DNA, RNA, total proteins and histories has been made on the developing endosperm of Linaria bipartita (Vent.) Willd.
    When the micropylar and chalazal haustoria become differentiated in a five celled endosperm, the haustorial structures show a higher content of the metabolites than the central endosperm cells. The few starch grains that are seen in the haustorial cells, completely disappear as soon as the endosperm proper starts dividing. The nuclei of the endosperm haustoria do not show a higher content of DNA than the other endosperm nuclei. The protein and RNA content are very high in young haustoria. However, these metabolites get gradually depleted as the haustorial cells start degenerating.
    From cytochemical evidences as well as developmental and positional data, a nutritive function has been ascribed to the endosperm haustoria. It has been found that the endosperm haustoria do not provide any nutrition to the embryo directly, but only to the developing endosperm. An interesting correlation between plants with endosperm haustoria and the time of degeneration of their antipodals has been also discussed.
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  • I. Some taxa of Chenopodium
    Ryuso Tanaka, Akio Tanaka
    1980 Volume 45 Issue 1-2 Pages 257-269
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    1. Karyomorphological studies were carried out in halophytic and nonhalophytic Chenopodium.
    2. Halophytic C. glaucum was dipolid with n=9, 2n=18; semi-halophytic C. acuminatum var. japonicum was tetraploid with n=18, 2n=36, non-halophytic C. album was hexaploid with n=27, 2n=54, C. album var. centrorubrum hexaploid with 2n=54, and C. ambrosioides var. pubescens n=16, 2n=32.
    3. The five taxa were found to have similar karyomorphological features categorized into the same ‘simple chromocenter type’ at resting stage, proximal and gradient heterochromatic type at prophase, and homogeneous type in size and symmetric type in arm-ratio at metaphase.
    4. Morphological features of chromosomes were found to be correlated to the phylogenetic interrelationships in taxa, while no particular feature was found in relation to halophytic habit, except for polyploidy.
    5. It was proposed that the morphological features of the chromosomes appear not as the product of adaptive reaction to the environmental conditions but as the product of phylogenetic reaction.
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  • Prakash Narain
    1980 Volume 45 Issue 1-2 Pages 271-279
    Published: June 25, 1980
    Released: March 19, 2009
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    Two tetraploid (2n=44) cultivars of Gloriosa (clone Nos. 73 and 6) have been discovered showing an extremely interesting and unusual course of meiotic behaviour during metaphase I. An analysis, however, indicated that 92.72 per cent pollen mother cells possessed one nucleus 4.15 per cent contained from 2 to 7 nuclei and remaining 2.05 per cent cells, were enucleate.
    The majority of the cells while uninucleate, had variable chromosomes number ranging from one fragment of a chromosome to full complement of n=22 or even upto 2n=48 chromosomes. Furthermore, nearly 48.6 percent PMC, both uninucleate and polynucleate has non-synchronisation in their chromosomes and/or nuclear developments. In the present work, the situations and possible reasons leading to such abnormalities were worked out and discussed.
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  • N. N. Bhandari, P. Soman, Mrinal Bhargava
    1980 Volume 45 Issue 1-2 Pages 281-291
    Published: June 25, 1980
    Released: March 19, 2009
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    A qualitative histochemical analysis of insoluble polysaccharides, starch, RNA and total proteins during the development of female gametophyte of Argemone mexicana L. has been conducted. Ontogenetically, the plant exhibits a monosporic, Polygonum type of embryo sac.
    Cytoplasmic polysaccharides and starch grains exhibit considerable changes during megagametogenesis. At the archesporial stage, the nucellus stains uniformly. From the MMC to the tetrad stage, the walls of these cells take a deeper stain than the cytoplasm. The degenerating megaspores stain very intensely. Wall of the egg is weakly PAS positive in the chalazal region, but stains strongly in the micropylar region. Synergids also stain intensely in the micropylar region. Antipodals have a PAS positive wall all around, but the cytoplasm is weakly positive.
    Nucellar cells under the MMC start accumulating starch grains and the number increases till the formation of functional megaspore. In the coenocytic stages and the mature embryo sac, larger grains are found in cells closer to the embryo sac and smaller grains in cells away from the embryo sac.
    RNA and total proteins parallel each other in their distribution. The archesporial cell stains moderately for them. There is a decline in the staining intensity in MMC. There seems to be no conspicuous difference in the distribution of RNA and total proteins in the four megaspores in a tetrad. Nucellar cells near the MMC and subsequent stages of megasporo and megagametogenesis show lesser staining for these metabolites as compared to the cells away from MMC. This trend continues till the mature embryo sac stage, when the chalazal nucellar cells stain deeply for RNA and total proteins. Among the constituents of the embryo sac, the antipodals appear to be the most metabolically active, as is revealed by the staining intensity.
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  • Tomas P. Pessacq
    1980 Volume 45 Issue 1-2 Pages 293-295
    Published: June 25, 1980
    Released: March 19, 2009
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    The incorporation of tritiated uridine into the nucleolus and its associated chromatin of avian neurons is studied. The nucleolar chromatinic complex of this cellular type seems to incorporate the labeled precursors of the RNA previously than other cellular parts.
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  • II. Male meiosis in 8 species of Crotalaria
    R. C. Verma, S. N. Raina
    1980 Volume 45 Issue 1-2 Pages 297-306
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Detailed meiosis was studied in eight species. All the species are diploid (n=8, 2n=16). Meiosis in C. brevifolia and C. brownei is reported for the first time. When taken in conjunction with other data, there is an overwhelming evidence that the basic number of the genus is eight.
    C. juncea, C. intermedia, C. brevifolia, C. brownei, C. burhia, C. verrucosa show regular 8 bivalents in majority of the cells. The univalents when present, are in low frequency, ranging from 0-2 per cell. C. lanceolata was characterized by the presence of an average 4.56 univalents per cell. Their range was from 2 to 10. In C. intermedia and C. lanceolata few trivalents and quadrivalents were observed. Anaphase I otherwise normal in other species, showed bridges with or without fragments, precocious division of univalents, unequal disjunction, lagging bivalents in C. lanceolata and C. retusa. As many as three bridge fragment configurations were observed in C. retusa. Recombination index is highest in C. verrucosa and lowest in C. lanceolata.
    Heterozygosity is mainly due to features like reduced pairing, reduced chiasma frequency, paracentric inversions, and/or breakage reunion bridges and localized chiasmata. Much of the evolution in this genus, in nature, appears to have taken place through gene mutations at diploid level. Polyploidy has not played a dominant role.
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  • VI. Evolutionary trends and relationships in the genus Nymphaea
    P. P. Gupta
    1980 Volume 45 Issue 1-2 Pages 307-314
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Cytogenetical investigations were carried out on the Indian populations, both wild and cultivated of the genus Nymphaea. The chromosome counts revealed a polyploid series ranging from diploid to octoploid levels based on x=14. In majority of the members, various abnormalities in the mitotic and meiotic systems have been noticed. Pollen sterility and seedlessness were also found to be fairly high. The present findings along with earlier published work have been taken into consideration to trace the evolutionary trends and relationships in Nymphaea. Polyploidy, weak development of isolating mechanism, structural changes of chromosomes and gene mutations appear to have involved for the evolution in this genus.
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  • Thomas E. Jensen, Robert P. Ayala
    1980 Volume 45 Issue 1-2 Pages 315-326
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Ultrastructural observation of isolates of Anabaena and Nostoc revealed the presence of variable diameter microtubule-like inclusions in Anabaena sp. (B-378), N. zetterstedtie, N. ellipsosporum (B-1623), N. punctiforme (1629), Nostoc sp. (389) and Nostoc sp. (387) and plasma membrane associated microtubule-like inclusions in N. ellipsosporum (B-383) and N. punctiforme (1629).
    Variable diameter microtubule-like inclusions were found mainly in groups primarily in the central cytoplasm. They varied in diameter from 9.5 to 22nm and measured up to 1μm in length. They were found only in the small cuboidal cells of the various cell sizes and shapes observed in the cultures.
    Plasma membrane associated microtubule-like structures were always oriented with the long axis perpendicular to the plasma membrane, and measured 15nm in diameter and up to 0.2μm in length.
    Neither kind of microtubule-like structure is depolymerized by colchicine or preserved by potassium permanganate fixation. The structures are compared to similar structures in other cells.
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  • Ram S. Verma
    1980 Volume 45 Issue 1-2 Pages 327-333
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The effect of different temperatures on the duration of nuclear cycle in Zea mays (single cross hybrid ‘Seneca 60’) root meristem cells, was studied with autoradiographic techniques and it was shown that all component phases of the nuclear cycle are shortened by an increase in temperature from 20 to 35°C. The durations of total nuclear cycle at 20, 25, 30, and 35°C were 16.5, 9.9, 7.0, and 4.4 hours respectively while the durations of mitosis were 2.68, 1.10, 0.83, and 0.43 hours respectively. 85-90 percent of the nuclear cycle is required for interphase, while the remaining 10-15 percent of the cycle is occupied by mitosis. The mean mitotic indices at 20, 25, 30, and 35°C were 9.8, 9.1, 5.3, and 4.9 percent respectively.
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  • A. B. Prasad, A. K. Das
    1980 Volume 45 Issue 1-2 Pages 335-341
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Dry and dormant seeds (10% moisture) of Lathyrus sativus L. var. P10, P24, P288, P293, P585 and LC76 were irradiated with 10, 20, 30, 40 and 50 kR gamma rays. Both control and irradiated seeds of variety P288 was treated with 0.2 MES for six hours. Albino, Xantha, Albo-Xantha, Xanthalba, Albo-viridis, Virescence, Chlorina, Albescence, Tigrina and Maculata were the general types of chlorohyll mutations observed in all the six varieties at M2 generations.
    The spectrum of chlorophyll mutations was found to be dependent on the nature of genotypes. This was further noted to have linear relationship with doses. Maximum chlorohyll mutations were observed in LC76 which was proved to be more sensitive than rest of other varieties.
    High frequency of mutations was recorded in P288 as a result of differential and combined treatment of 0.2% MES which was seen to be as effective as 20 kR gamma rays.
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  • Aiko Sakai-Wada
    1980 Volume 45 Issue 1-2 Pages 343-351
    Published: June 25, 1980
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Electron microscopic studies on the substructure of chromatin were carried out using chromosomes in the first meiotic metaphase from pollen mother cells of Tradescantia reflexa. The chromosomes were composed of 300Å chromatin threads formed by coiling of 100Å chromatin thread. The 100Å chromatin threads contained globular structures of about 70Å diameter. The location of DNA, protein and RNA were studied by treatment of the chromosomes with DNAase, 0.25N HCl containing 2M NaCl and RNAase.
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