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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 20 (1997), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In many coastal areas, synthetic surfactants are present as pollutants in the chemical composition of sea spray. Their phytotoxic action in synergism with sea salt is well known. This paper examines the early effects of an anionic surfactant (sodium alkylbenzene sulphonate = ABS) on the anatomy and ultrastructure of Pinus pinea L. needles. Three successive treatments in the open field on Pinus pinea trees about 2 m in height were carried out in the month of August. The crowns of the trees were sprayed with an aqueous solution containing 1000 g m−3, and subsequently the current-year needles were observed by light microscopy, as well as by scanning and transimission electron microscopy. A few days after the treatment the needles had turned yellow. The results of the microscopical analysis show that the surfactant is absorbed prevalently through the stomata and that it causes deterioration of the epistomatal wax structures and induces alterations in the stomatal guard cell walls. Lastly, it causes degeneration of the protoplasm in cells of the mesophyll, beginning with the cells closest to the stomatal openings. The efficiency of both photosynthesis and gaseous exchange processes may be affected.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5044
    Keywords: callus histology ; fennel ; growth regulators ; in vitro morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Different NAA plus kinetin or BA combinations were tested on Francia Pernod fennel seedlings for callus induction and plant regeneration. Callogenesis from hypocotyls was obtained in all auxin/cytokinin-containing media. The organogenic response was observed especially in presence of NAA plus kinetin. The highest frequency of shoot regeneration was found when the auxin and kinetin were used at a 1:1 ratio. Moreover, a prolonged culture period increased shoot formation. Somatic embryogenesis was tested on several fennel populations. The results gave evidence of the genotypic importance. Two different protocols were used for somatic embryo induction. Using the first protocol among the different fennel genotypes tested, only Francia Pernod showed embryogenic capacity. In this case, from a primary non-embryogenic callus cultured for 12 months in presence of 2,4-D, an embryogenic secondary callus was produced. When transferred to the medium without 2,4-D (agarized or liquid), this gave embryogenic plants in high frequency. As far as the second embryogenic method is concerned, secondary embryogenic callus developed only in the presence of 2,4-D plus kinetin in Francia Pernod genotype. Thereafter, the replacement of those growth regulators by GA3 into the medium greatly increased the somatic embryo development, especially in `Francia Pernod', but also in `Aboca erbe' callus, a population with a very poor embryogenic capacity. In Francia Pernod, the primary and secondary (embryogenic) calli showed different morphological and histological responses, either when the secondary callus was induced by 2,4-D alone or by 2,4-D plus kinetin. Ontogenetic processes leading to somatic embryo formation are described in this context.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The authors have prepared the following compounds: C6H5COOCH3, TiCl4; 2-CH3-C6H4COOCH3, TiCl4; 2,6-(CH3)2-C6H3COOCH3, TiCl4; 2,4,6-(CH3)3-C6H2COOCH3, TiCl4.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 47 (1964), S. 1172-1181 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The authors have prepared the 1 : 1 adducts between -AgClO4, and the hydrocarbons benzene, toluene and m-xylene. The electronic absorption spectra of their solutions in the corresponding hydrocarbon exhibit each an absorption band between 2770 Å and 2900 Å. The same bands are found in solutions of AgClO4,in the hydrocarbons mentioned and in mesitylene.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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