Karyological features and cytotaxonomy of the tribe Vernonieae (Asteraceae)

• Published in: Plant systematics and evolution Vol. 285; no. 3-4; pp. 189 - 199
• Main Authors: Salles-de-Melo, Maria Rita Cabral, de Lucena, Rodrigo Mendonça, Semir, João, de Carvalho, Reginaldo, de Cássia Araújo Pereira, Rita, Benko-Iseppon, Ana Maria
• Format: Journal Article
• Language: English
• Published: Vienna Vienna : Springer Vienna 01.03.2010; Springer; Springer Vienna; Springer Nature B.V
• Subjects: Biological evolution; Biological taxonomies; Biomedical and Life Sciences; chromosome number; Chromosomes; Deoxyribonucleic acid; DNA; Dysploidy; Evolution; Fluorochrome staining; Genera; Heterochromatin; Hybridization; Interphase; Life Sciences; Original Article; Plant Anatomy/Development; Plant chromosomes; Plant Ecology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Plants; Ploidies; Polyploidy; Prophase; Satellite DNA; Species; Taxa; Chromosome numbers; Polyploidy; Heterochromatin; Dysploidy; Fluorochrome staining
• ISSN: 0378-2697; 1615-6110; 2199-6881
• DOI: 10.1007/s00606-010-0277-2

Chromosome numbers are reported for 29 populations of 19 Vernonieae taxa collected mainly in the northeastern region of Brazil. Among them, data for five genera (Blanchetia, Rolandra, Pithecoseris, Stilpnopappus and Vanillosmopsis) are here reported for the first time, and the first chromosome counts are presented for 12 species. Chromosome numbers are quite diverse among and sometimes within genera, especially in the controversial and large subtribe Vernoniinae. The numbers varied from 2n = 18 to 2n = ~72. The main karyoevolutionary mechanism seems to be dysploidy, while polyploidy is probably associated with ancient hybridization processes generating most paleotetraploid genera. All studied species presented semi-reticulated interphase nuclei and proximal-early condensing behavior in prophase to prometaphase. In one species (Vernonia condensata with 2n = 40) fluorochrome staining with CMA/DAPI revealed five chromosome pairs bearing subterminal CMA⁺/DAPI⁻ heterochromatin, probably NOR-associated, revealing the existence of low amounts of satellite DNA. The role of these features in the evolution of the tribe is discussed, revealing some interesting aspects for understanding of the Vernonieae karyoevolution, especially regarding neotropical members.