Estudo quimiotaxonômico de sementes de espécies de Mimosoideae (Leguminosae)

Abstract

The content and fatty acid composition of seed lipids in 8 species from the Mimosoideae were analysed. The species investigated belong to 4 Tribes: Acacieae (Acacia farnesiana e A. langsdorffii), Ingeae (Chloroleucon foliolosum e Pithecellobium dulce), Mimoseae (Stryphnodendron coriaceum e S. rotundifolium ) e Parkieae (Parkieae pendula e P. platycephala). In addition, the soluble protein content, the hemagglutinating activity, and the protein electrophoretic pattern of the seeds from these species were also determined. In relation to the seed lipids, the results showed that the fatty acid composition and their ratios may be useful as taxonomic markers for the differentiation of genera belonging to different Tribes of the Mimosoideae, as well as for discrimination of species from the sarne genus. On the other hand, it was not found any taxonomic correlation for the occurence of hemagglutinating activity in the seeds of the 8 species investigated at the Tribe leveI. However, the presence of hemagglutinating activity (or hemolysis) as well as its specificity, that is, the type of erythrocytes agglutinated (or hemolysed), proved to be useful for the discrimination of species from the same genus. The analysis of the electrophoretic profile of the seed proteins showed, in all the species examined, the presence of 2 major groups of protein bands: one group that comprises high molecular weight proteins with mobility similar to that observed for the purified lectin from Parkia platycephala (60 KDa), and a second one constituted of low molecular weight proteins. However, each species exhibited a unique protein pattern that promptly differentiated it from the others.