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  • 1
    ISSN: 1432-2145
    Schlagwort(e): Key words Cupressus dupreziana ; DNA content ; Endosperm ; Reproduction ; Flow cytometry ; Gymnosperm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Nuclear DNA content of embryo and endosperm from mature and immature Cupressus dupreziana A. Camus seeds was estimated using laser flow cytometry. Relative DNA content of endosperm nuclei corresponded to four ploidy levels: 2C, 4C, 6C and 8C. The embryo nuclei invariably exhibited a diploid pattern. In all endosperm tissue analyzed no haploid nucleus was found. This is problematic since, in gymnosperms, endosperm and female gametes originate from one functional haploid megaspore produced by meiosis. The possible origin and derivation of C. dupreziana endosperm are discussed in light of previous results concerning the two other Mediterranean cypresses, C. sempervirens and C. atlantica.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 101 (2000), S. 574-579 
    ISSN: 1432-2242
    Schlagwort(e): Key words 2n pollen ; Cupressus dupreziana ; Gymnosperms ; Flow cytometry ; Reproduction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Size and DNA content of pollen of Cupressus dupreziana A. Camus, a highly endangered Mediterranean conifer, were assessed by cytomorphological observations and flow cytometric analyses and then compared to C. sempervirens L. pollen. Mature C. dupreziana pollen was composed of two uninucleated types of pollen grains differing in size. Around 35% of the grains exhibited a size similar to C. sempervirens pollen, while 65% exhibited a larger diameter. However only one peak of fluorescence was detected by flow cytometry. DNA content of C. dupreziana pollen was twice the DNA content of C. sempervirens pollen. Comparison of DNA contents of mature and germinating pollen revealed that mature pollen of both species were arrested in the G2 phase. Comparison with the DNA content of somatic tissue (2C) provided evidence for the production of unreduced pollen in C. dupreziana. This unexpected feature in gymnosperms is discussed in terms of reproductive strategy of this species.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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