Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/60924
Type: Artigo de periódico
Title: Karyological features and cytotaxonomy of the tribe Vernonieae (Asteraceae)
Author: Salles-de-Melo, MRC
de Lucena, RM
Semir, J
de Carvalho, R
Pereira, RDA
Benko-Iseppon, AM
Abstract: 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 = similar to 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.
Subject: Chromosome numbers
Dysploidy
Polyploidy
Fluorochrome staining
Heterochromatin
Country: Austria
Editor: Springer Wien
Rights: fechado
Identifier DOI: 10.1007/s00606-010-0277-2
Date Issue: 2010
Appears in Collections:Unicamp - Artigos e Outros Documentos

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