Variações morfológicas, moleculares e fitoquímicas do Complexo geonoma maxima (poit.) Kunth (arecaceae) na Amazônia: elucidação de um problema taxonômico

Abstract

Genus Geonoma known by its little taxonomically resolved representatives constitutes a favourable group for an integrated study on different segments. In order to do that, morphological, chemical, and molecular characters of four Geonoma species, known to constitute a species complex, were analysed for the intent of a taxonomical understanding. The study of the morphological characters points out four distinct species: Geonoma maxima, Geonoma chelidonura, Geonoma spixiana and Geonoma ambigua, based mainly on the variations presented by leaves and inflorescences. Geonoma maxima presents pinnate linear-lanceolate leaves; two or three times branched inflorescences and pits distributed far apart in spiral. Geonoma ambigua presents forked leaves; just one-branched inflorescence, long rachillae and pits close to one another in spiral. Geonoma chelidonura presents leaves with four to five oblong-speared fellies; thin rachillae, branched twice and pits far apart in spiral. Geonoma spixiana presents whole, forked and stongly plicate leaves; one-branched inflorescence, bifid or trifid, thick and erect rachillae, with pits deeper and distributed in well-defined series or rows. The study of the DNA through AFLP markers, revealed two groups, one of them constituted by Geonoma maxima and Geonoma chelidonura, and the other by Geonoma spixiana. Flavonoidic profile multivariate analysis showed Geonoma maxima with just 15% of proximity in relation to Geonoma chelidonura and Geonoma spixiana, while these two present higher proximity, 42%. Cytogenetic analysis allows to point out superficially that Geonoma chelidonura presents chromosome number between 26 and 28 (2n=26 or 28). No information concerning this matter was obtained for the remaining species. It is concluded there is some exchange of genes between Geonoma maxima and Geonoma chelidonura, even with different phenotypes in their totality, and that Geonoma ambigua and Geonoma spixiana are separate taxa.