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  • 1
    Electronic Resource
    Electronic Resource
    A proposed index for measuring ionospheric scintillations
    Amsterdam : Elsevier
    Planetary and Space Science 17 (1969), S. 1069-1073 
    Details
    ISSN: 0032-0633
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0032-0633(69)90114-7
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  • 2
    Electronic Resource
    Electronic Resource
    Keto Acids in Pollen and Pollen Tubes of Sesbania aegyptica (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 39 (1977), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Pollen and pollen tubes of Sesbania aegyptica Pers. contain α-ketoglutaric acid, oxaloacetic acid and pyruvic acid. Changes in the keto acids have been correlated with their corresponding amino acids during different phases of germination. It is suggested that keto acids were readily turned over during the elongation of pollen tubes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1977.tb09290.x
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of Gibberellic Acid, (2-Chloroethyl) Phosphonic Acid, Actinomycin-D and Cycloheximide on the Activity and Leaching of Some Hydrolases in Pollen Suspension Cultures of Crotalaria juncea (1979)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 45 (1979), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Gibberellic acid (GA3) 20 mg 1−1 and (2-chloroethyl) phosphonic acid (Ethephon) 10 mg 1−1 enhanced pollen tube length in Crotalaria juncea L. GA3 markedly increased the activity of amylase, acid phosphatase and β-glucosidase and enhanced leaching of amylase and acid phosphatase enzymes. The rise in the activity level and leaching of amylase and acid phosphatase after Ethephon treatment was comparatively less than that of GA3 and the response to Ethephon was restricted to the 45 and 90 min period of culturing. Ethephon did not affect the activity/leaching of β-glucosidase significantly. Actinomycin-D (Act.D) 25 mg l−1 and Cycloheximide (CH) 10 mg 1−1 reduced the tube growth as well as activity of these enzymes suggesting their de novo synthesis during pollen tube growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1979.tb02586.x
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  • 4
    Electronic Resource
    Electronic Resource
    Synergistic effect of gibberellic acid and indole-3-acetic acid on rooting in stem cuttings of Abelmoschus esculentus Moench (1978)
    Springer
    Planta 138 (1978), S. 111-112 
    Details
    ISSN: 1432-2048
    Keywords: Abelmoschus ; Auxin ; Gibberellin ; Root formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Indole-3-acetic acid (IAA) and gibberellic acid (GA3) enhanced the formation of roots on the stem cuttings of Abelmoschus esculentus. The effect increased considerably when both IAA and GA3 were applied together.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392926
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  • 5
    Electronic Resource
    Electronic Resource
    The genus Argemone (1973)
    Springer
    Theoretical and applied genetics 43 (1973), S. 329-334 
    Details
    ISSN: 1432-2242
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Crosses between three diploid (A. mexicana; A. subfusiformis; A. albiflora) and one tetraploid (A. ochroleuca) Argemone species were made. The F1's were cytogenetically analysed. All the triploid hybrids were sterile and did not set any seed. In the species there was predominantly bivalent pairing (14II; 28II) and high pollen and seed fertility. The F1's displayed different configurations, e.g. I, II and III, and pollen fertility was low; the capsules were shrunken and did not contain any seed. In the two combinations mexicana X ochroleuca and subfusiformis X ochroleuca, pairing was identical and both auto- and allosyndesis were observed. The number of univalents, bivalents and trivalents varied in the three combinations but the number of associations did not differ significantly. In the albiflora X ochroleuca combination as many as 13 trivalents were observed. In general a negative correlation was observed between univalents and chiasmata per cell. However, chiasma frequency and paired associations displayed a positive correlation. It is deduced that sufficient similarities existed between one of the ochroleuca and the three diploid species genomes; the remainder of the ochroleuca genome had homologous chromosomes. Apparently A. ochroleuca carried enough cryptic intergenomal homologies which ordinarily remained unexposed. In the hemizygous state however, as in the F1's, there was intergenomal pairing. In an attempt to resolve the conflict between homology and bivalent pairing in the species, a diploidizing genetic mechanism is envisaged. Alternatively an acute propensity to preferential pairing caused bivalent formation. Such a system or systems caused meiotic isolation of various genomes and instituted normal fertility. Furthermore, the segmental allotetraploid nature of A. ochroleuca is concluded. The cytogenetic relationship between mexicana and ochroleuca is appraised.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275261
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  • 6
    Electronic Resource
    Electronic Resource
    Cytogenetic studies on the F1 hybrid ofLolium multiflorum ×L. rigidum and the species relationship in the genusLolium (1967)
    Springer
    Theoretical and applied genetics 37 (1967), S. 261-264 
    Details
    ISSN: 1432-2242
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Lolium multiflorum ×L. rigidum wurden erfolgreich gekreuzt und die Chromosomen in F1-Hybriden bezüglich ihrer Struktur und Paarung mit denen der Eltern verglichen. Die Chromosomen der Eltern ließen eine weitgehende Homologie erkennen, aber in gewissem Ausmaß deutete sich auch eine Differenzierung an. Diese Beobachtung läßt den Schluß zu, daß die beiden Arten relativ eng verwandt sind und sich phylogenetisch nahestehen. Das vorgelegte Modell weist darauf hin, daß die Differenzierung der SektionenCraepalia undEulolium höchstwahrscheinlich von einem gemeinsamen Vorfahr ausging. Dieser existierte vermutlich im Mittelmeergebiet als einjähriger Fremdbefruchter mit symmetrischem Karyotyp.
    Notes: Summary Successful crosses have been made betweenLolium multiflorum ×L. rigidum and theF 1 hybrids cytologically compared with the two parents with respect to karyomorphology and chromosome pairing. The hybrid showed considerable homologies between the parental chromosomes though some amount of differentiation had also occurred. The extent of differentiation suggests that phylogenetically the species are related and possibly separated quite recently. A model is presented to account for the differentiation of sectionsCraepalia andEulolium from a common stock. Presumably the ancestral form existed in the Mediterranean and was, briefly, an outbreeder with symmetrical karyotype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00593236
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of Variations in Temperature on Meiosis in Gagea reticulata Schultes (1960)
    [s.l.] : Nature Publishing Group
    Nature 187 (1960), S. 805-806 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A few plants of G. reticulata were collected from the same locality growing late in the season (May). A number of meiotic irregularities were recorded in these individuals. These comprised non-pairing of chromosomes, early disjunction, the presence of bridges and laggards with unequal distribution ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/187805b0
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  • 8
    Electronic Resource
    Electronic Resource
    Comparison of Changes in Total Electron Content along Three Paths (1970)
    [s.l.] : Nature Publishing Group
    Nature 226 (1970), S. 1113-1114 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE total electron content of the ionosphere during the March 7, 1970, solar eclipse was measured along paths towards three geostationary satellites from a ground station at Hamilton, Massachusetts. The Sun was 96 per cent eclipsed at the ground at Hamilton. The total electron content (TEC) was ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2261113a0
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  • 9
    Electronic Resource
    Electronic Resource
    Chromosomal polymorphism in Festuca arundinacea (1966)
    Springer
    Chromosoma 18 (1966), S. 1-18 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Within F. arundinacea ten exotic populations each crossed with an indigenous bred form S. 170, and their hybrids, were grouped into fertile, partly fertile and sterile categories. Four were fertile hybrids with bivalent pairing (20.75 to 20.99/cell) and high pollen fertility. Two were partly fertile with univalents, and bivalents (18.26 to 19.54/cell) and rarely multivalents. The pollen fertility was low. Four hybrids were completely sterile with low or nil pollen fertility. The bivalent formation was low (12.94 to 14.25/cell) while the frequency of univalents and multivalents was high. There was evidence of structural changes of both gross (multivalents formation due to translocation; univalents due to inversions and deletions) and cryptic types from these hybrids. This diversity in the chromosomal constitution of several populations could be the result of several factors, including wide geographical distribution, climatic and edaphic diversity of the population, polyploid nature of the species, restriction of the gene pool and successful mode of vegetative propagation. In some of the populations an isolating mechanism has been effectively established and may well represent an initial stage in speciation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00326440
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  • 10
    Electronic Resource
    Electronic Resource
    Cytological relationships in theConvolvulus pluricaulis complex (1968)
    Springer
    Genetica 39 (1968), S. 250-256 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract InConvolvulus pluricaulis Chois. two forms (2n=18, 36) along with one colchicine-autotetraploid have been investigated morphologically and cytologically. The diploid regularly formed 9II although in the “off-season” plants certain irregularities were observed including formation of unreduced pollen grains. The natural tetraploid and the colchicine-autotetraploid had mean frequencies of configurations of 1.56IV+14.04II+1.48I and 2.95IV+0.56III+11,43II+0.8I, respectively. The mode of chromosome association in the two types of tetraploids was comparable. A comparison of the morphological characters of the two tetraploid types, further, suggested close similarity. In addition they were indistinguishable from the diploid from except being gigas. From these data it is inferred that the natural tetraploid presumably arose as a result of direct duplication of the diploid form, through the chance fusion of unreduced spores. The lower quadrivalent frequency of the natural polyploid is ascribed to a gradual shift towards bivalent association accompanying natural selection for fertility. The taxonomic status of the two forms (2x, 4x) is discussed and the varietal status accorded to the tetraploid form is supported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02324468
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