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Hybridization and Polyploidy: Cytogenetic Indications for Hoffmannseggella (Orchidaceae) Species Evolution

Author(s): Julia Yamagishi-Costa | Eliana Regina Forni-Martins

Journal: International Journal of Botany
ISSN 1811-9700

Volume: 5;
Issue: 1;
Start page: 93;
Date: 2009;
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Keywords: meiotic behavior | Campos rupestres | Laelia | chromosome evolution | cytotypes

In the present research through chromosome counts utilizing root meristems and immature ovaries and/or observation of meiotic behavior from floral buds, we analysed seven Hoffmannseggella species and confirmed the basic number of x = 20. From the seven species analyzed, one presented polyploidy (H. briegeri (Blumensch. ex Pabst) V.P.Castro and Chiron, 2n = 80), one presented both diploid (2n = 40) and polyploid (2n = 80) cytotypes (H. rupestris (Lindley) V.P. Castro and Chiron) and the five remaining species presented n = 20/2n = 40 chromosomes. Polyploid species/cytotypes presented aneusomatic root tissues. Meiotic abnormalities, like monovalents, early disjunction of bivalents and putative tetravalents were observed in several species. We suggest that hybridization and polyploidy are, if not the major, at least very important mechanisms for the evolution of species and that these events are probably occurring in the present, possibly being responsible for many taxonomic divergences within the group.
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Tango Rapperswil
Tango Rapperswil