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  • 1
    Electronic Resource
    Electronic Resource
    Fine structure of differentiated chromosome segments during the meiosis of pollen mother cells of Allium cepa (1977)
    Springer
    Cellular and molecular life sciences 33 (1977), S. 728-729 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Differentiated chromosome segments were observed during studies of pollen mother cells of A. cepa during the first meiotic division. Their structure is like those of the nucleolar organizing region (NOR) described in A. cepa microspores. It is suggested that these differentiated chromosome segments correspond to the secondary constrictions seen under the optical microscope.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01944153
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Calcium in electron-dense globoids during pollen grain maturation in Chlorophytum elatum R.Br. (1997)
    Springer
    Planta 203 (1997), S. 413-421 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Calcium (pollen germination) ; Chloro-phytum (pollen maturation) ; Globoid (electron dense) ; Phytate metabolism ; Pollen grain maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. The localization, elemental composition and quantitative changes in insoluble, electron-dense globoids observed in the course of pollen grain development in Chlorophytum elatum R.Br. have been investigated. During pollen maturation, small electron-dense globoids were only found within larger electron-light vesicles in the cytoplasm of the vegetative cell. The number and diameter of the electron-dense globoids increased during pollen grain maturation, and decreased after pollen germination. By energy-dispersive X-ray microanalysis, the presence of calcium, magnesium and phosphorus was detected in these globoids. The results are discussed in the light of previous findings with regard to phytate metabolism and the role of calcium in pollen germination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050208
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of allergenic protein (Ole e I) in the endoplasmic reticulum of the developing pollen grain of olive (Olea europaea L.) (1995)
    Springer
    Planta 196 (1995), S. 558-563 
    Details
    ISSN: 1432-2048
    Keywords: Allergenic protein (immunolocalization) ; Endoplasmic reticulum ; Olea ; Pollen (olive)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The monoclonal antibody OL-1 and transmission electron microscopy were used to locate immunologically the major allergen of olive pollen. Ole e I, during pollen grain development. Within the pollen grain, allergenic proteins are located in the cisternae of the rough endoplasmic reticulum. Our findings indicate that the synthesis of these proteins starts in the vegetative cytoplasm of olive pollen during the early maturation stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203656
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Ubiquitin and ubiquitin-conjugated proteins in the olive (olea europaea l.) pollen (2000)
    Springer
    Sexual plant reproduction 12 (2000), S. 285-291 
    Details
    ISSN: 1432-2145
    Keywords: Key words Ubiquitin ; Ubiquitin-conjugated proteins ; mRNA ; Pollen olive tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A study of free ubiquitin and ubiquitinated proteins has been carried out in olive (Olea europaea L.) during the late stages of pollen development and during in-vitro pollen hydration. As described in relatively few plant species, immunoblot experiments carried out using crude protein extracts have shown a reduction in the free ubiquitin level taking place during the mature pollen stage. This reduction does not coincide with a parallel reduction in the level of the corresponding transcripts, as detected by RT-PCR analysis, suggesting the existence of a post-transcriptional regulatory mechanism. Relatively high levels of free ubiquitin are quickly restored upon in-vitro pollen hydration. TEM immunocytochemical localisation of ubiquitin-conjugated compounds in the mature pollen grain showed the antibodies bound to the cytoplasm, the chromatin and the nucleolus of the vegetative and generative cells. Within the cytoplasm, labelling was concentrated in the cytosol, the endoplasmic reticulum membranes and minuscule vesicles associated to the Golgi apparatus. The fibrillar material adhering to the exine, and probably derived from the tapetum, also showed gold particles. Lipid bodies, aperture regions, mitochondria, the intine and the cell wall were devoid of labelling. The changes observed throughout pollen development, as well as the specific localisation, reflect the involvement of the ubiquitin-mediated degradative pathway in regulation of pollen metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970050196
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructural expression of cytoplasmic male sterility in sugar beet (Beta vulgaris L.) (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 22-32 
    Details
    ISSN: 1432-2145
    Keywords: Cytoplasmic male sterility ; Ultrastructure ; Mitochondria morphometry ; Beta vulgaris L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of microspore mother cells (MMC) and tapetum in male-fertile and male-sterile anthers of Beta vulgaris L. was compared at the electron microscope level. These studies were complemented by morphometric analyses of mitochondria in both tissues through successive stages of microsporogenesis. The earliest irregularities in the ultrastructure of male-sterile anthers were noted within the tapetum at the tetrad stage. These disturbances were initially expressed by a slight reduction in mitochondrial size and the appearance of concentric configurations of endoplasmic reticulum. As development proceeded, a further decrease in mitochondrial size become more conspicuous and was accompanied by a reduction in ribosome population and a failure of the tapetum to produce Ubisch bodies. This failure to produce Ubisch bodies is reflected in the underdevelopment of sterile microspore exine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227579
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Endoplasmic reticulum as a storage site for allergenic proteins in pollen grains of several Oleaceae (1995)
    Springer
    Protoplasma 187 (1995), S. 111-116 
    Details
    ISSN: 1615-6102
    Keywords: Allergenic protein ; Oleaceae ; Pollen ; Endoplasmic reticulum ; Immuno-localization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of mature pollen grains of several Oleaceae species (Olea europaea, Fraxinus excelsior, Syringa vulgaris, Ligustrum vulgare, andForsythia suspensa) was studied and the immunolocalization of Ole e I, the major allergen of olige pollen, was determined by immunogold labelling. The five Oleaceae pollens studied here showed different intensities of labelling. The Ole e I allergen was localized throughout the rough endoplasmic reticulum. The absence of gold particles in other cell compartments, such as nuclei, pastids, mitochondria, dictyosomes, lipid bodies, and cell wall, as well as the absence of labelling in control preparations, indicate the specificity of immunolocalization. We conclude that endoplasmic reticulum of the mature pollen grain is a storage site for allergenic proteins and is probably also involved in their synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280238
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    Paper (German National Licenses)
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