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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 1-2 
    ISSN: 1432-2145
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 16-24 
    ISSN: 1432-2145
    Keywords: Pollen tube ; Organelle movement ; Actin microfilament bundles ; Iris pseudacorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Continuous observation of organelles and other cytoplasmic inclusions in the older stretches of living pollen tubes of Iris pseudacorus shows that in the more attentuated parts of the protoplast they move along single, mainly longitudinally oriented fibrils, corresponding to those previously isolated from other species and shown to contain bundles of uniformly polarised actin microfilaments. The traffic associated with each fibril is unidirectional, but organelles move along them independently, sometimes with conspicuously different velocities. Larger columns of cytoplasm passing along the tube are associated with several such fibrils, as revealed in occasional discontinuities and also in columns isolated from the tube in suitable medium without fixation. The dimensions of the individual fibrils suggest that the bundles of actin microfilaments are not likely to be enclosed in a unit membrane corresponding to a tonoplast. If so, the nature of the continuous cavities traversed by numerous fibrils in the older parts of the pollen tube requires reappraisal, since these are more likely to be volumes of attentuated cytoplasm comparable with that of the central cavity of the sieve tube than vacuoles of the normal plant-cell type.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 36-45 
    ISSN: 1432-2145
    Keywords: Pollen protoplast ; Pollen tube ; Lilium longiflorum ; Cell wall regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplasts from pollen grains of Lilium longiflorum regenerate amorphous cellulosic cell walls in culture, during which some precursors of cellulose are polymerized, thus producing progressively harder cellulosic cell walls as the period of culture continues. It is presumed that the components of the cell wall regenerated during 1 week in culture differ from those of the intine of the pollen grain wall. The regenerated cell wall is formed by means of large smooth vesicles; in addition, numerous coated vesicles and pits aid in wall regeneration. The pollen tube that germinates from the 8-day-old cultured protoplast has numerous Golgi bodies and many vesicles which build the pollen tube wall. The tube wall has two layers just like a normal pollen tube wall.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 51-58 
    ISSN: 1432-2145
    Keywords: Congruity backcrossing ; Recurrent backcrossing ; Incongruity ; Interspecific genetransfer ; Phaseolus vulgaris ; Phaseolus acutifolius
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Recurrent or introgressive backcrossing of Phaseolus vulgaris — P. acutifolius hybrids with either P. vulgaris or P. acutifolius increased fertility, as measured by pollen stainability and seed per pod from non-manipulated flowers, while invariably resulting in loss of traits from the non-recurrent parent. When hybrids were backcrossed with each of the parent species in alternate generations (congruity backcrossing), fertility decreased in early generations but gradually increased in later generations. By the fourth or fifth generation, congruity-backcross hybrids produced numbers of seeds per pod from non-manipulated flowers comparable to those of parent species, although the percent of stainable pollen tended to be lower. Congruity-backcross hybrids were intermediate to parent species when pedigrees contained equal representation of parents but favored the majority parent when pedigrees were unbalanced. Individuals exhibiting symptoms of developmental incongruity, such as abnormal leaflet number, foliar variagation, or unusual growth patterns, occurred in each generation. However, completely new characteristics appeared after the second backcross generation, presumably due to recombination. Backcrossing to both parent species in alternate generation reversed incongruity, allowing selection for fertility without loss of traits from one of the parent species.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 97-102 
    ISSN: 1432-2145
    Keywords: Generative cell ; Isolation ; Scanning electron microscopy ; Immunofluorescence ; Video-enhanced microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Generative cells were isolated from the pollen grains of three angiosperm species by a method similar to that previously reported for Haemanthus katherinae (Baker). Both the external appearance and the internal structure of the isolated generative cells were observed by light and scanning electron microscopy. The dynamic changes occurring in the cells after they had been liberated from the pollen grains were recorded by video-enhanced microscopy. The distribution of microtubules in the isolated cells was revealed by immunofluorescence.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 119-123 
    ISSN: 1432-2145
    Keywords: Self-incompatibility ; Incongruity ; Interspecific hybridization ; Cut-style pollination ; Mentor pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Interspecific crosses were made between seven Lilium species, viz. L. candidum, L. concolor, L. dauricum, L. henryi, L. longiflorum, L. nepalense and L. rubellum. A complete diallel cross was carried out between these seven species, including self- and intraspecific pollinations using three pollination methods: normal pollination on the stigma, pollination on the ovary after cutting the style, and pollination on the stigma with the aid of ‘mentor’ (non-functional, compatible) pollen. Embryo rescue, starting 35 days after pollination, was applied to all interspecific combinations. The percentage of successful crosses was about 2.8% after normal pollination, 5.4% after cut-style pollination and 3.8% with the mentor pollen technique. Crosses with L. nepalense were exceptional in that embryos died during the embryo culture phase. Seventeen cross combinations (including 4 reciprocals) yielded 62 embryo plantlets from 839 interspecific pollinations.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 150-155 
    ISSN: 1432-2145
    Keywords: Nicotiana ; Malus ; Pollen tube growth ; Protein synthesis ; Pollen development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pollen tubes grown in vitro were pulselabelled for 5–30 min with [14C]amino acids, and the proteins analysed by SDS-PAGE and fluorography. In Nicotiana tabacum, the qualitative pattern of the synthesized proteins did not change significantly when the pollen was cultured for 1–24 h in different media, but total protein synthesis declined as pollen tube growth slowed down and was very low in non-growing tubes. The patterns showed preferential synthesis of proteins with apparent molecular masses of 63 and 65 kDa. The 65 kDa species, which is not synthesized during pollen maturation and is absent in ungerminated pollen grains, appears as the most intensely labelled band in both soluble and insoluble protein fractions, but accumulates as a protein non-covalently bound to pollen structures. It is also preferentially synthesized in N. sylvestris, N. alata, and in apple pollen tubes, and probably plays an important role in tube wall formation. In Nicotiana tabacum, the labelling of the 65 kDa, protein is not specifically reduced upon strong inhibition of transcription by actinomycin D, which indicates a post-transcriptional level of induction of its synthesis in germinating pollen.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 164-172 
    ISSN: 1432-2145
    Keywords: Chamaenerion ; Cytoskeleton ; Gasteria ; Megasporogenesis ; Meiosis ; Microtubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Gasteria and Chamaenerion, microtubular configurations were visualized immunocytochemically during meiosis and megasporogenesis in order to study their relationship to cell development, meiotic divisions and selection of the functional megaspore. In Chamaenerion, the intensity of the fluorescence found in megaspores was weaker than that found in Gasteria. Both plants exhibited concentrations of microtubules around the meiocyte nuclei during pachytene-diplotene. Preprophase bands were not observed. In Chamaenerion, cytoplasmic microtubules radiating from meiocyte nuclei were found at late prophase, the dyad stage and in the functional megaspore; in Gasteria, they were observed only at the dyad stage and in the functional megaspore. During the second meiotic division of Gasteria, dividing cells and their nuclei exhibited differences in volumes. Also, the two microtubular spindles of the dyad cells had different widths. Fluorescence indicating the presence of the cytoskeleton diminished during maturation of the large functional megaspores in both plants, whereas in the three degenerating smaller megaspores, fluorescence intensity persisted. Our conclusion is that only an indirect relationship exists between the organization of the microtubular cytoskeleton and selection of the functional megaspore.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 195-201 
    ISSN: 1432-2145
    Keywords: Basidiomycetes ; Agrocybe aegerita ; Incompatibility genes ; Parasexuality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Crosses were performed between homokaryons of Agrocybe aegerita having the same allele at the A incompatibility gene but different B alleles. Heterokaryotic mycelia originating from crosses between two complementary auxotrophs were characterized by their instability on complete medium and extensive anastomosis between hyphae. Diploid mycelia were selected by plating oidia recovered from these heterokaryons onto minimal medium. These mycelia were characterized by the production of larger oidia than those of homokaryons, the release of a brown pigment when growing on complete medium and extensive hyphal anastomoses. Diploids retained the two B incompatibility functions of their homokaryotic parents and gave rise to a diploid/haploid dikaryon when crossed with a compatible homokaryon. Nearly 1% of the oidia recovered from heterokaryons were diploid. These nuclear fusion frequencies as well as the production of brown pigments enabled the identification of diploid strains on complete medium. In this way, crosses between wild prototrophic strains were successfully performed. Somatic recombination was induced following the treatment of diploid mycelia with haploidizing compounds. Selection based on the inability of mycelia to produce the brown pigments on complete medium led to selection of strains homoallelic at the B locus.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 223-227 
    ISSN: 1432-2145
    Keywords: Self-incompatibility ; In vitro assay ; Malus domestica ; Style proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An in vitro assay in which self-incompatible pollen of Malus domestica is selectively inhibited is described. This assay involves heat-labile substances diffusing from the stylar tissues — in particular, glycoproteins found in the protein extract of styles. In the presence of the self-style extract, a dramatic decrease in total protein concentration in the culture medium was revealed at 30-min germination. Pretreatment of the self-pollen with 100 mM glucose prevented this drop in protein level; moreover, tube growth was entirely restored. A possible explanation in terms of protein-carbohydrate complementation is suggested.
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