Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Self-incompatibility in Acacia retinodes: Site of pollen-tube arrest is the nucellus (1986)
    Springer
    Planta 169 (1986), S. 245-250 
    Details
    ISSN: 1432-2048
    Keywords: Acacia ; Nucellus ; Ovule ; Pollen tube arrest ; Sell-incompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In self-incompatible Acacia retinodes Schldl. var. uncifolia J.M. Black there is no inhibition of self pollen tubes before entry into the ovule, but the frequency of fertilized embryo sacs observed after self pollination is only 0.09–0.24 of that observed after outcrossing. Fluorescence- and light-microscope studies of sectioned, squashed or cleared whole ovules indicate that most self pollen tubes are arrested within the first or second layer of cells of the nucellus. The probability that nucellar arrest represents a primitive feature of self-incompatibility is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392321
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural analysis of plastids in angiosperm pollen tubes (1989)
    Springer
    Sexual plant reproduction 2 (1989), S. 70-76 
    Details
    ISSN: 1432-2145
    Keywords: Pollen tube ; Plastid ; Chromoplast ; Light ; Tannic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When Rhododendron pollen tubes are cultured in the dark, electron-dense bodies are present that appear to be a metabolically altered form of a proplastid that is difficult to fix for electron microscopy, and whose membranes may not be intact. When similar pollen tubes are cultured in a dark/light regime, ultrastructurally well-defined proplastids are present after fixation in glutaraldehyde with PIPES buffer and tannic acid, followed by osmic acid. This fixation technique also gave the best ultrastructural images of those proplastids in pollen tubes grown in the dark. Pollen tube plastids have the potential to become chromoplasts when cultured in a dark/light regime as evidenced by the presence of branched tubules characteristic of these organelles. Light appears to be a hitherto neglected environmental factor involved in regulating pollen tube growth. This improved fixation procedure demonstrates the bilayered nature of the membranes surrounding sperm cells and the existence of cytoplasmic channels connecting sperm cell and pollen tube plasma membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191993
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The male germ unit of Rhododendron: quantitative cytology, three-dimensional reconstruction, isolation and detection using fluorescent probes (1989)
    Springer
    Sexual plant reproduction 2 (1989), S. 254-264 
    Details
    ISSN: 1432-2145
    Keywords: Generative cell ; Sperm cell ; Quantitative cytology ; Mitochondria ; Plastids ; Immunofluorescence ; Actin ; Tubulin ; Video-image processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sperm cells of Rhododendron laetum and R. macgregoriae differentiate within the pollen tube about 24 h after germination in vitro. Threedimensional reconstruction shows that the sperm cells are paired together, and both have extensions that link with the tube nucleus, forming a male germ unit. Quantitative analysis shows that the sperm cells in each pair differ significantly in surface area, but not in cell volume nor in numbers of mitochondria or plastids. When isolated from pollen tubes by osmotic shock, the sperm cells became ellipsoidal and surrounded by their own plasma membrane, while a proportion remained in pairs linked by the inner tube plasma membrane. Both generative and sperm cells are visualized in pollen tube preparations by immunofluorescence with anti-tubulin and anti-actin monoclonal antibodies (MAbs) combined with H33258 fluorescence of the nuclei. Video-image processing shows the presence of an axial microtubule cage in the generative cells, and some microtubules are present in the cytoplasmic extensions that clasp the tube nucleus. Following sperm cell division, the extensive phragmoplast between the sperm nuclei is partitioned by the plasma membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195585
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Sperm cells of the pollen tubes of Brassica: Ultrastructure and isolation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 226-234 
    Details
    ISSN: 1432-2145
    Keywords: Male germ unit ; Sperm cells ; Isolation ; Pollen tubes ; Brassica napus ; Pollen-tube inner plasma membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sperm cells of pollen tubes grown both in vivo and in vitro form a male germ unit. Extensions from both sperm cells of each pollen tube are closely associated with the tube nucleus. A high yield (2.7 × 104. 20 mg−1 pollen grains germinated) of intact sperm cells was obtained following release by osmotic shock from pollen tubes grown in vitro. Structural integrity of isolated sperm was maintained by isolation at low temperature in an osmotically balanced medium. At 4° C many isolated sperm pairs were still enclosed within the pollentube inner plasma membrane. Sperm cells not enclosed within this membrane no longer remained connected as a pair. During isolation vesicles formed on the sperm cell surface from disruption of the fibrillar components bridging the periplasmic space. Both in the pollen tube and after isolation the sperm nucleus is in close association with at least one region of the sperm plasma membrane. Sperm isolated at room temperature showed the presence of nucleopores, and nuclei were euchromatic, instead of heterochromatic as in intact sperm in the pollen tube.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190009
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Self-incompatibility in the nitrogen-fixing tree, Acacia retinodes: quantitative cytology of pollen tube growth (1985)
    Springer
    Theoretical and applied genetics 69 (1985), S. 481-488 
    Details
    ISSN: 1432-2242
    Keywords: Acacia ; Self-incompatibility ; Pollen tube growth ; Wattle/S-gene ; Nitrogen-fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 10×10 diallel of crosses involving trees in two natural populations of A. retinodes (Leguminosae: Mimosoideae) showed a high level of self-incompatibility, with ISI (Index of Self-Incompatibility) of 0.08. In both self- and cross pollinations, pollen tubes grew through the style to the ovules within 11 h. Tube growth rate is approximately similar in both types of mating: 3.3 to 4.5 μm/min for the first 6 h, and 1.2 to 2.0 μm/min for the succeeding 5 h. Three potential explanations for self incompatibility are proposed: (1) an S-gene controlled system in which pollen tubes are arrested in the nucellus of the ovule; (2) sperm: egg interactions at fertilization and (3) action of post-zygotic lethal genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00251089
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Characterization of cloned rat ribosomal DNA fragments (1981)
    Springer
    Molecular genetics and genomics 182 (1981), S. 25-30 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two Charon 4A lambda bacteriophage clones were characterized which contain all and part of the 18S ribosomal DNA of the rat. One clone contained two Eco RI fragments which include the whole 18S ribosomal RNA region and part of 28S ribosomal RNA region. The other clone contained an Eco RI fragment which covers part of 18S ribosomal RNA region. There were differences between the two clones in the non-transcribed spacer regions suggesting that there is heterogeneity in the non-transcribed spacer regions of rat ribosomal genes. The restriction map of the cloned mouse ribosomal DNA. Eco RI, Hind III, Pst I, and Bam HI sites in 18S ribosomal RNA region were in the same places in mouse and rat DNA but the restriction sites in the 5′-spacer regions were different.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422762
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Pollination-related characteristics in the mimosoid legumeAcacia terminalis (Leguminosae) (1987)
    Springer
    Plant systematics and evolution 157 (1987), S. 49-62 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Mimosoideae ; Acacia terminalis ; Bee- and bird-pollination ; extrafloral nectaries ; intraspecific variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intraspecific variation has been found for several pollination-related characteristics in two isolated populations of the self-incompatible treeAcacia terminalis: floral characteristics including colour and flowering time; style length; size and colour of extrafloral nectaries on the leaf petioles; chemical components of the extrafloral nectar; different taxa of bee pollinators; and frequency differences in bird pollinators. These differences possibly reflect the evolution of two different pollination syndromes within this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00939180
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Plastid development and ferritin content of stigmas of the legumesAcacia, Lotus andTrifolium (1983)
    Springer
    Protoplasma 116 (1983), S. 213-218 
    Details
    ISSN: 1615-6102
    Keywords: Stigma ; Legumes ; Plastid ; Ferritin ; Secretion ; Pollination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Inclusions of ferritin have been observed in plastids from the stigma and stylar tissues of several legumes. The ferritin particles occurring in the stroma of plastids appear as paracrystalline clusters inAcacia or as fingerprint-like patterns inLotus andTrifolium. InAcacia, developmental studies indicate there is a transition in plastid structure from chloroplasts in the meristematic stigma cells, through amyloplasts, amoeboid amyloplasts to oleoplasts in mature stigmas. Following pollination,Acacia stigma cells may undergo holocrine secretion, with cytoplasmic contents becoming electron dense and undergoing autolysis. The ferritin along with other cellular constituents is available for uptake during the heterotrophic nutrition of the pollen tubes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279842
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...