Karyotype analysis and DNA content in some species of Chrysolaena (Vernonieae, Asteraceae)
VIA DO PICO, G. M.; DEMATTEIS, M.
TAYLOR & FRANCIS LTD
Lugar: Londres; Año: 2013 p. 864 - 873
Cytogenetic characterization by karyotyping and determination of DNA content by flow cytometry of five species of Chrysolaena (Vernonieae, Asteraceae) was performed. This is the first study of nuclear DNA content realized in the genus. The 2C-values were compared with the ploidy level and the total karyotype length (TKL) of each species. Mitotic analysis revealed a basic chromosome number x=10 for all entities and different ploidy levels, from diploid (2n=2x=20) to octoploid (2n=8x=80). All species showed bimodal karyotypes composed by metacentric and submetacentric chromosomes. The average chromosome size (ML) varied from 1.86 µm to 2.70 µm, while the total karyotype length ranged from 18.65 µm to 80.55 µm. The intrachromosomal asymmetry index (A1) varied from 0.27 to 0.38, while the interchromosomal asymmetry index (A2) ranged from 0.19 to 0.25. A new cytotype is reported for the first time for C. propinqua (Hieron.) H.Rob. Accessories chromosomes found in C. verbascifolia (Less.) H.Rob., C. cognata (Less.) Dematt., C. flexuosa (Sims) H.Rob. and C. propinqua are also reported as new.