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  • 1
    Electronic Resource
    Electronic Resource
    Ontogeny of intruding non-periplasmodial tapetum in the wild chicory,Cichorium intybus (Compositae) (1989)
    Springer
    Plant systematics and evolution 167 (1989), S. 149-164 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Cichorium intybus ; Tapetum ; pollen ; exine ; pollenkitt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The tapetal development ofCichorium intybus L. is investigated using LM and TEM and discussed in relation to the development in other species. During the second meiotic division the tapetal cells become binucleate and lose their cell walls. They intrude the loculus at the time of microspore release from the meiotic callose walls, which means that a locular cavity is never present in this species. During pollen development they tightly junct the exine, especially near the tips of the spines. During the two-celled pollen grain stage they degenerate and most of their content turns into pollenkitt. Until anther dehiscence they keep their individuality, which means that these intruding tapetal cells never fuse to form a periplasmodium. The ultrastructural cytoplasmatic changes during this development are discussed in relation to possible functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00936403
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Ripe pollen structure and histochemistry of some gymnosperms (1999)
    Springer
    Plant systematics and evolution 217 (1999), S. 81-99 
    Details
    ISSN: 1615-6110
    Keywords: Gymnosperms ; pollen ; exine ; intine ; histochemistry ; polysaccharide reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some aspects of pollen cytology at dispersal were studied in 12 species of gymnosperms. The pollen grains differed in: 1. volume and cell number; 2. polarization of external structure and internal cell components; 3. wall thickness, especially of the intine, and the resulting percentage of cell volume with respect to total pollen grain volume; 4. stratification and chemical nature of the various intine layers; 5. nature and location of polysaccharide reserves; 6. morphological differences between the dry and hydrated states and phenomena related to hydration; 7. presence and site of orbicles. The various characters are compared and discussed in relation to the length of the reproductive cycle and the relations between the male gametophyte and its female counterpart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984923
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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