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  • Microautoradiography  (2)
  • Sucrose unloading  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Transport processes in stimulated and non-stimulated leaves of Mimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 7-17 
    Details
    ISSN: 1432-2285
    Keywords: Leaf movements ; Mimosa ; Osmotic mechanisms ; Phloem translocation ; Sucrose unloading ; Turgor release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Mature leaves of Mimosa pudica L. or parts of them were exposed to 14CO2, and translocation was recorded by macroautoradiography. It was observed that considerable amounts of labelled photoassimilates were accumulated in pulvini when the leaf was stimulated. In non-stimulated leaves, no such accumulation of label was observed. Microautoradiographs of pulvinar regions of the non-stimulated leaf showed 14C- label restricted to the phloem. When stimulated, the 14C- label was unloaded from the phloem of the pulvini. Labelled photoassimilates appeared most concentrated in the walls of the collenchymatous cells and beyond in the extensor region of the motor cortex. There, label was accumulated in the apoplastic compartments. Stimulation causes a sudden phloem unloading of sucrose, and its accumulation in the apoplast lowers the water potential which eventually exceeds the osmotic potential of the extensor cells of the motor cortex. By removal of cytoplasmic water the motor cells lose turgidity which results in the closing movement of the leaflets, and — some seconds later — in the bending down of the petiole. In late afternoon night-stimulation triggers sucrose unloading in secondary pulvini. During phases of relaxation, labelled material is taken up by motor cells of the extensor, which concomitantly gain turgor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196974
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Influence of phloem transport on flower abscission in Hibiscus rosa-sinensis (1990)
    Springer
    Trees 4 (1990), S. 128-135 
    Details
    ISSN: 1432-2285
    Keywords: Fruit abscission ; Hibiscus rosa-sinensis ; Microautoradiography ; Phloem transport ; Starch deposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Flowering cultivars of Hibiscus rosa-sinensis L. were either cross-pollinated or self-pollinated. Fruit set was observed on 52% of the cross-fertilized flowers, while only 4.6% of the self-fertilized flowers were not abscised. Once during fruit and seed growth, the subtending leaf was exposed to 14CO2, and translocation of labelled photoassimilate was recorded by macro- and microautoradiography. Phloem transport into the raphe occurred in both fruits with fertilized and fruits with non-fertilized ovules. Since empty ovules showed some sink strength, it is assumed that growth of vegetative seed-tissue signalizes the retardation of completion of the abscission process. During fruit growth a considerable amount of starch is deposited in the distal layer of the abscission zone. Part of this starch is consumed during growth of cross-fertilized fruits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225776
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Regulation of photoassimilate allocation in Pinus sylvestris seedlings by the nutritional status of the mycorrhizal fungus Suillus variegatus (1991)
    Springer
    Trees 5 (1991), S. 36-43 
    Details
    ISSN: 1432-2285
    Keywords: Microautoradiography ; Mycorrhiza ; Pinus sylvestris ; Suillus variegatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings of Pinus sylvestris L. were grown on defined nutrient solutions on carbon filters, either sterile or infected with the basidiomycete Suillus variegatus O. Kuntze. After mycorrhizas were established, the shoot of the seedling was subjected to 14CO2 photosynthesis. 14C-labelled photoassimilates were translocated to both mycorrhizas and non-infected root tips. Microautoradiographs of mycorrhizas indicated that omission of external sugars did not affect the formation of mycorrhizas; 14C-photoassimilates were supplied to cortex, Hartig net and the mantle of hyphae surrounding the rootlet. Nutrient solution containing sugars (malt extract, glucose) enhanced the growth of the fungus. As a consequence, 14C-photoassimilates from the seedling were accumulated in the mantle, but defence mechanisms of the host cannot be excluded. When soluble nitrogen was omitted from the nutrient solution and replaced by chitin precipitated on the filter-bearing mycorrhizas, the fungus appeared strongly labelled in the mantle, where the fungal chitinase provided soluble nitrogen compounds, necessary for the growth of the seedling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225333
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Transport processes in stimulated and non-stimulated leaves ofMimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 7-17 
    Details
    ISSN: 1432-2285
    Keywords: Leaf movements ; Mimosa ; Osmotic mechanisms ; Phloem translocation ; Sucrose unloading ; Turgor release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Mature leaves ofMimosa pudica L. or parts of them were exposed to14CO2, and translocation was recorded by macroautoradiography. It was observed that considerable amounts of labelled photoassimilates were accumulated in pulvini when the leaf was stimulated. In non-stimulated leaves, no such accumulation of label was observed. Microautoradiographs of pulvinar regions of the non-stimulated leaf showed14C- label restricted to the phloem. When stimulated, the14C- label was unloaded from the phloem of the pulvini. Labelled photoassimilates appeared most concentrated in the walls of the collenchymatous cells and beyond in the extensor region of the motor cortex. There, label was accumulated in the apoplastic compartments. Stimulation causes a sudden phloem unloading of sucrose, and its accumulation in the apoplast lowers the water potential which eventually exceeds the osmotic potential of the extensor cells of the motor cortex. By removal of cytoplasmic water the motor cells lose turgidity which results in the closing movement of the leaflets, and — some seconds later — in the bending down of the petiole. In late afternoon night-stimulation triggers sucrose unloading in secondary pulvini. During phases of relaxation, labelled material is taken up by motor cells of the extensor, which concomitantly gain turgor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01196339
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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