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  • 1
    Electronic Resource
    Electronic Resource
    Seasonal course of translocation and distribution of 14C-labelled photoassimilate in young trees of Larix decidua Mill (1989)
    Springer
    Trees 3 (1989), S. 185-191 
    Details
    ISSN: 1432-2285
    Keywords: Larch ; Larix ; Phloem transport ; Photoassimilate ; Translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Young trees of Larix decidua, in their 4th and 5th year of development, were permitted to photoassimilate a pulse of 14CO2 at different times throughout the growing season. After chase periods between 1 h and 7 days, the distribution of 14C in these plants was determined. CO2 fixation followed a maximum curve with highest rates of photosynthesis of 123 ± 4 μmol CO2·h-1·mg chl-1 in June. Translocation of 14C assimilate was observed throughout the growing season. The main quantity of fixed 14C was always retained in the fed leaves. Radiocarbon moved basipetally into the roots at all times, particularly in spring and late summer. Sprouting young shoots and leaves at the stem apex attracted assimilate in spring. Incorporation of 14C into soluble low-molecular-weight substances prevailed; less radioactivity was incorporated into insoluble polymeric compounds. Distribution of 14C among the sugar, amino acid and organic acid fraction was determined. Labelled free sugars were analysed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225352
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  • 2
    Electronic Resource
    Electronic Resource
    Structure and development of sieve cells in the secondary phloem of Larix decidua Mill. as related to function (1989)
    Springer
    Trees 3 (1989), S. 192-209 
    Details
    ISSN: 1432-2285
    Keywords: Autoradiography ; Fine structure ; Larch ; Larix decidua ; Sieve cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Only one or two layers of sieve cells of the previous year's phloem in lateral branches of Larix decidua persist as fully mature cells. Immature sieve cells or cambial derivatives that have not completed differentiation may also over-winter. Periclinal cell divisions of the vascular cambium were first observed by mid-April. During the short period of greatest cambium activity (mid-April to mid-May), the early phloem is laid down. Late phloem is formed over a much longer period, from mid-May to late September. Microautoradiography revealed that only mature sieve cells of the early phloem are involved in translocation of 14C assimilates in June. The fine structure of actively translocating sieve cells is described. The impact of structure on long-distance transport of assimilates is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225353
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  • 3
    Electronic Resource
    Electronic Resource
    CO2-Fixierung und Stofftransport in benthischen marinen Algen (1973)
    Springer
    Planta 112 (1973), S. 253-263 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary After local assimilation of NaH14CO3 by an old frond of Laminaria hyperborea, radioactive photosynthate is translocated to the growing region of the thallus. The pathway of this long-distance transport was studied by histoautoradiography. Cellular localization of the conducting channels was accomplished by new autoradiographic methods including freeze-substitution and 1 μm-cuttings of epoxy resin embedded tissue. In the autoradiographs, patches of silver grains overlying single trumpet-filaments (=Trompetenzellen) indicated that downward translocation occurs in these cells only. It could be shown that predominantly young trumpetfilaments contain the bulk of labeling. It is concluded that the young filaments rather than the older ones are particularly active in translocation. A lateral movement of labelled material was not observed except in the growing region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385329
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  • 4
    Electronic Resource
    Electronic Resource
    Der autoradiographische Nachweis trittierter wasserlöslicher Substanzen in den Siebröhren von Cucurbita und Cucumis (1970)
    Springer
    Planta 91 (1970), S. 96-110 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When D-Glucose-6-T is applied to small areas of the leaf blade of Cucumis or Cucurbita, a translocation of labelled material within the veins and the petiole down to the internodes of the axis can be demonstrated by chemical methods and by histoautoradiography. The translocated material was identified by thin layer and paper chromatography as stachyose, raffinose, and sucrose. A dry mounting autoradiographic technique was elaborated which prevented any secondary diffusion of water soluble substances. In autoradiograms of longitudinal and cross sections of veins, petioles and internodes, tritium can be localized within single sieve tubes of exporting bundles. Usually the centre of activity corresponds to the cytoplasmic material or the slime-plugs and to the sieve plates. Since sucrose, stachyose and raffinose are the main labelled translocated substances in these experiments, there is little doubt that with certain precautions such autoradiograms may present a real picture of the long-distance translocation of assimilates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386095
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  • 5
    Electronic Resource
    Electronic Resource
    Fine structure, distribution and frequency of plasmodesmata and pits in the cortex ofLaminaria hyperborea andL. saccharina (1982)
    Springer
    Planta 154 (1982), S. 385-392 
    Details
    ISSN: 1432-2048
    Keywords: Laminaria ; Parenchyma transport ; Phaeophyta ; Pit fields ; Plasmodesmata ; Symplastic transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Prior to a long-distance transport of photoassimilate in the sieve elements ofLaminaria, a parenchyma transport across the cortex must occur. It is suggested that this transport is a symplastic one. The structural basis for this statement, continuous cytoplasmic interconnections of cells along the transport pathway, is demonstrated here forL. hyperborea andL. saccharina. The distribution, size, and frequency of pit fields in cell walls of all planes were determined. The data suggest that the conductivity for assimilate transport in the cortex is highest in the long axis of the thallus, not radially across the cortex. The fine structure, arrangement and number of plasmodesmata in pit fields were studied. The estimated flux rates and the anatomical findings clearly point to a symplastic parechyma transport of photoassimilate in the cortex ofLaminaria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01267803
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  • 6
    Electronic Resource
    Electronic Resource
    Distribution and immunolocalization of stachyose synthase in Cucumis melo L. (1991)
    Springer
    Planta 185 (1991), S. 479-486 
    Details
    ISSN: 1432-2048
    Keywords: Cucumis (stachyose synthesis) ; Intermediary cells (leaf minor veins) ; Stachyose synthase (immunolocalization, distribution)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Indirect evidence for the site of stachyose biosynthesis has been provided by determining the occurrence and distribution of stachyose, raffinose and galactinol, the donor of the galactosyl moiety for stachyose synthesis, in Cucumis melo L. cv. Ranjadew. Studies of enzyme activities for the synthesis of these sugars and their distribution in different plant organs and isolates has led to the conclusion that stachyose is synthesized mainly in mature leaves and seeds. Nevertheless, stachyose-synthase activity varied with leaf age, the developmental stage of a plant, the growing season and the plant cultivar used. No stachyose or stachyose-synthase activity could be detected in isolated mesophyll protoplasts and chloroplasts, whereas both were found in a minor-vein-enriched fraction isolated from mature leaves. The conclusion that stachyose biosynthesis is associated with minor veins was confirmed by immunolocalization of the enzyme. Positive specific immunoreactivity of stachyose synthase with polyclonal anti-stachyose-synthase antibodies, labeled with protein A-gold, was detected in intermediary cells of leaf minor veins. The implication of this local synthesis of the main transport sugar for phloem loading in mature leaves of Cucumis melo is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202956
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  • 7
    Electronic Resource
    Electronic Resource
    Zum Nachweis tritiierter Assimilate in den Siebröhren von Cucurbita (1968)
    Springer
    Planta 83 (1968), S. 111-114 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary After application of D-glucose-6-T to small areas of leaf surfaces of Cucurbita, radioactivity — mainly sucrose-T — could exclusively be localized by histoautoradiography (“dry-technique”) within single sieve tubes of exporting bundles. The centre of activity corresponded to the “slime”-plugs (in crosssection-autoradiograms) of the sieve tubes and to the sieve plates (in longitudinal sections). It is concluded that only the sieve tubes are the conducting channels for the long-distance transport of those substances which are labeled with tritium in these experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385139
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  • 8
    Electronic Resource
    Electronic Resource
    Stachyose synthesis in mature leaves of Cucumis melo. Purification and characterization of stachyose synthase (EC 2.4.1.67) (1991)
    Springer
    Planta 184 (1991), S. 525-531 
    Details
    ISSN: 1432-2048
    Keywords: Cucumis ; Galactosyltransferase ; Stachyose synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Galactinol: raffinose-6-galactosyltransferase (EC 2.4.1.67), a stachyose synthase, was extracted from mature leaves of Cucumis melo cv. Ranjadew and was purified to homogeneity by (NH4)2SO4 precipitation, ion-exchange chromatography, gel-filtration and non-denaturing polyacrylamide gel electrophoresis. A specific activity of 516 μkat · mg-1 and a 160-fold purification was achieved. The pH optimum of the enzyme reaction was found to be 6.8 in sodium-phosphate buffer, and the temperature optimum 32° C. The purified enzyme was very sensitive towards SH-poisons but its reaction was hardly affected by changes in the ion composition of the assay medium. The two-substrate enzyme was specific for galactinol and raffmose; uridine-diphosphate galactose and p-nitrophenyl-α-d-galactoside as well as melibiose were not accepted by the purified enzyme. Stachyose synthesis was competitively inhibited by concentrations 〉4 mM raffinose as well as 2.5 mM galactinol. The K m values determined under non-saturating conditions were 3.3 mM for raffinose and 7.7 mM for galactinol. Myoinositol was a strong competitive inhibitor with a K i of 1.8mM. Galactinol was hydrolyzed in the absence of raffinose with a K m of 0.8 mM. The pure enzyme is a protein with a molecular weight of at least 95 kDa and an isoelectric point of 5.1. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the presence of two subunits of 45 and 50 kDa. Polyclonal antibodies from rabbit were obtained which were specific for the native enzyme but cross-reacted with other proteins separated under denaturing conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197902
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  • 9
    Electronic Resource
    Electronic Resource
    Zum Assimilattransport in wachsende Früchte von Phaseolus vulgaris (1968)
    Springer
    Planta 80 (1968), S. 89-95 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Nach 14CO2-Assimilation im Blatt wurde der Eintransport markierter Assimilate in wachsende Früchte von Phaseolus vulgaris histoautoradiographisch untersucht. Die 14C-markierten Substanzen werden danach im Phloem der Fruchtstiele transportiert, in keinem Falle konnte eine Assimilatleitung in anderen Geweben des Fruchtstiels bemerkt werden. Hierzu im Widerspruch stehende Befunde von Bachofen und Wanner werden diskutiert.
    Notes: Summary Leaves of fruiting plants of Phaseolus vulgaris were exposed to 14CO2 in the light. The movement of 14C-labelled assimilates from these leaves into the growing fruits was studied by histoautoradiography (“dry technique”). The fact that 14C-activity could be detected within the fruit stalks exclusively in the areas of the phloem may favor the hypothesis that also in this case assimilates are transported only via the phloem. The xylem was always free of 14C. The contradictory results of Bachofen and Wanner are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387193
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Pulsatile Flow Testing of a Biomaterial/Polymer Composite Heart Valve Obtained Through Tissue Engineering (2003)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 426-432 (Aug. 2003), p. 3067-3072 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/07/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.426-432.3067.pdf
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