Chromosomal evolution in Pleurothallidinae (Orchidaceae: Epidendroideae) with an emphasis on the genus Acianthera: chromosome numbers and heterochromatin
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Data
2015-05-01
Autores
Oliveira, Irenice Gomes de
Moraes, Ana Paula [UNESP]
Almeida, Erton Mendonça de
Assis, Felipe Nollet Medeiros de
Cabral, Juliano Sarmento
Barros, Fabio de
Felix, Leonardo Pessoa
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ISSN da Revista
Título de Volume
Editor
Wiley-Blackwell
Resumo
In this study, we analysed chromosome number variation and chromomycin A(3)/4,6-diamidino-2-phenylindole (CMA/DAPI) banding patterns in 48 species belonging to 12 genera of subtribe Pleurothallidinae (Orchidaceae) in order to understand the chromosome evolution based on recent phylogenetic hypotheses and taxonomic treatments. All species had small chromosomes, with numbers ranging from 2n=20 in two Specklinia spp. to 2n=80 in an unidentified Octomeria sp. In Acianthera, the most highly represented genus in this study, a great diversity of chromosome number and pattern of fluorescent bands was observed, showing heterochromatin accumulation in Acianthera section Sicariae subsection Pectinatae. Interspecific ascending and, mainly, descending dysploidy were the main mechanisms of chromosome number evolution in subtribe Pleurothallidinae. For Pleurothallidinae, x=20 is suggested as the basic chromosome number, the same suggested for the related subtribe Laeliinae and for the whole tribe Epidendreae. The Brazilian species of the mega-genus Stelis had chromosomes with small amounts of heterochromatin and chromosome numbers based on x(2)=16. These are generally divergent from those reported for Andean and Meso-American species, but in agreement with the monophyletic hypothesis proposed for Stelis spp. with a Brazilian Atlantic distribution.
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Palavras-chave
Basic chromosome number, Chromosome number variation, CMA, DAPI, Cytotaxonomy, Dysploidy, Polyploidy, Reconstruction of ancestral state, Stelis
Como citar
Botanical Journal Of The Linnean Society. Hoboken: Wiley-blackwell, v. 178, n. 1, p. 102-120, 2015.