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  • 1
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The use of instrumental neutron activation analysis (INAA) in determining selected elements in biological materials has been reported by numerous authors. Some of these have detailed the use of INAA to determine an elemental analysis in tobaccos of various geographical origins. This paper describes the first use of INAA to measure the distribution of selected inorganic elements within the tobacco leaf at a single plant stalk position for one tobacco curing routine. Three replicate plots of a common bright tobacco cultivar were grown under normal cultural conditions characteristic for the bright variety. The tobacco leaves were sampled at selected positions in the leaf. The brigh tobacco was cured in a conventional flue-curing barn using standard practices. Immediately after collection, each individual sample was freeze-dried, crushed and sampled. The leaf midrib samples were prepared using a similar procedure. A subsample of about 100 mg was taken from each sample, sealed in a polyethylene bag, irradiated in a thermal neutron flux of 2×1017 n·m−2·s−1 in a pneumatic rabbit system, and subsequently counted to obtain the reported data. A standard reference material was used as a comparator to yield relative elemental concentrations for Ca, Mg, Mn, Na, K, Cl and Br. The data show that chlorine, potassium, sodium and calcium have definite concentration trends within the tobacco leaf. The data also show that some elements, e.g. Mn, were more uniformly distributed throughout the leaf.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 16 (1990), S. 1565-1576 
    ISSN: 1573-1561
    Keywords: Nicotiana ; Solanaceae ; Peronospora tabacina ; blue mold ; Alternaria alternata ; leaf surface chemistry ; diterpenes ; sucrose esters ; hydrocarbons ; spore germination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chromatographic procedures were utilized to isolate and purify components of tobacco cuticular extracts and leaf surface chemicals.In vitro microbial bioassays determined the influence of these leaf surface compounds on germination and germ tube morphology ofP. tabacina sporangia, the tobacco blue mold pathogen, and to a lesser extentAlternaria alternata, the tobacco brown spot pathogen. Exposure to 10 μg/cm2 of α- and β-duvatrienemonols, sucrose esters, or hydrocarbons did not inhibit germination, whereas germination was significantly decreased bycis-abienol.cis-Abienol did not inhibit sporangial germination when combined with sucrose esters or hydrocarbons at a combined 10 μg/cm2. Germination of sporangia was completely inhibited by α- and β-duvatrienediols. In contrast to a previous report, α-DVT-diol was more inhibitory than the β isomer. Toxic effects of the DVT-diols were not altered by pH. Diluting the DVT-diols to less than 0.1 μg/cm2 resulted in a small but significant stimulation of germination. Previously, the DVT-diols had been identified only as inhibitory toP. tabacina. None of the leaf surface chemicals affected germination ofA. alternata conidia.
    Type of Medium: Electronic Resource
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