Academic Journals Database
Disseminating quality controlled scientific knowledge

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

ADD TO MY LIST
 
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;
VIEW PDF   PDF DOWNLOAD PDF   Download PDF Original page

Keywords: meiotic behavior | Campos rupestres | Laelia | chromosome evolution | cytotypes

ABSTRACT
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.
Affiliate Program     

Tango Rapperswil
Tango Rapperswil