Karyology of Two Species of Genus Tabebuia   Gomes (Bignoniaceae)

Abstract

In accordance with Gentry (1982), Tabebuia chrysantha   (Jacq.) Nichols., is a species extremely polymorphic and probably T. capitata (Bur. & Schum.) Sandw. and T. subtilis could geographical and ecological variances of the same one. It could also form hybrid with T. ochracea; for such reasons, this group of species form a complex that hinders their identification taxonomically when the conventional tools are only used by classic taxonomy; putting forward the necessity to appeal to biosystematic studies. These plows the antecedents that drove to carry out the present work, in order to carrying out to chromosomal analysis of Tabebuia chrysantha and T.capitata, frequent species in the state Monagas, Venezuela; the first one proliferates in mountainous areas, the other ones in the region of the plains but very distant one of the other. Radicle meristem, colchicine at 0.05 %, NaCl at 0.03 % and Orcein FLP at 2 % were used for the separation of the chromosomes, measuring five cells per species. The results determined that T. chrysantha presents the chromosomes of greater size than T. capitata. The cariotipic formulas proposed are: T. chrysantha: 2n = 40 = 2M +26m + 12sm and T. capitata: 2n = 40 = 20m; these results seem to indicate that they are different species

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