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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 141 (1983), S. 243-255 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Caryophyllaceae ; Petrorhagia prolifera ; P. velutina ; P. glumacea ; P. nanteuilii ; Chromosome numbers ; karyotype ; meiotic behaviour ; polyploidy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cytogenetic investigations have been made in the fourPetrorhagia species and hybrids of the sectionKohlrauschia. The three diploid species show close similarities in chromosome number, size and morphology, with the exception ofP. velutina, where one pair of metacentric chromosomes is represented by a pair of telocentrics. Meiotic studies in hybrids indicate close genomic homology between the diploid species and also between the two floral forms ofP. prolifera. The tetraploidP. nanteuilii behaves as an allotetraploid forming only bivalents at meiosis and results suggest thatP. velutina andP. prolifera are the diploid progenitors of this species. Since meiosis in diploid and triploid hybrids results in extensive intergenomic pairing it is concluded that the natural tetraploid has a bivalent promoting mechanism that prevents pairing between the genomes of its diploid progenitors.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 139 (1981), S. 77-94 
    ISSN: 1615-6110
    Schlagwort(e): Caryophyllaceae ; Petrorhagia prolifera ; P. velutina ; P. glumacea ; P. nantueuilii ; Floral morphology ; breeding systems ; hybridization ; reproductive isolation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the diploid speciesP. prolifera, the evolution of autogamy has resulted in the presence of distinct selfing and outcrossing races. The change in breeding system toward autogamy is associated with a reduction in the size of floral features and a lower pollen production. The outbreeding populations have only been found in Greece, while the selfing populations have colonized much of Europe. The two races appear to be reproductively isolated from one another. —Petrorhagia sect.Kohlrauschia contains four species.P. glumacea is outbreeding and shows unilateral incompatibility with the small-flowered race ofP. prolifera and interfertility with the large-flowered race; althoughP. glumacea is sympatric with the large-flowered race, they do not appear to hybridize in the wild. Amongst the allopatric species, internal breeding barriers are also found. These may take the form of hybrid sterility or seed incompatibility.P. velutina is autogamous and reproductively isolated from all the other species of the section regardless of whether they are sympatric or allopatric. It is suggested that the evolution of autogamy has been an important factor in the spread ofP. velutina, the tetraploidP. nanteuilii, and the small-flowered race ofP. prolifera in Europe.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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