Anatomia foliar comparada em espécies de Oenocarpus Mart. (Arecaceae) de Belém, Pará, Brasil: uma contribuição taxonômica

Abstract

The objective of this work was to study the comparativo leaf-anatomy among Oenocarpus bacaba Mart., O. dislichus Mart., O. mapora H. Karst. and O. minor Mart. in order to evaluate if ones have useful, qualitativo, anatomical-differences to identify them, discussing so whether those species are anatomically uniform palms as belongs to Arecoideae sub-family in what the structural differences whether there're occur only to quantitativo levei according to bibliography. Standard plant anatomical techniques were utilized such as epidermal dissociation, transverso and longitudinal sections, maceration, stain and histochemistry too, making observations on light microscopy and scanning electron one. Common features for the four species' leaflets as amphistomatic lamina; heteromorphy epidermal tissue; smooth cuticle; epicuticular wax in the forms hooked filaments and rectangular plates; tetracytic stomata; apparently multicellular, non-glandular, two-filamented trichomes; dorsiventral mesophyll with brachysclereids, mucilage secretory structures, tertiary and III-type secondary vascular bundles were observed. However, cyclocytic stomata; expansion tissue's layer number; geometry and sclerenchyma's distribution of the midrid and ledge showed peculiar for leaflets of some species. The outer of the leaf-sheath, petiole and rachis resemble in anatomical organization on the studied ones of Oenocarpus Mart., but the middle and conter those regions in general are specifics for each one as regards the parenchyma tissue. Furthermore, leaf axis's vascular bundles were graded according to morphological variety itself at 44 types and got nine groups in. Libriform fibres; macrosclereids and astrosclereids; tracheids with annular, helical and denso helical wall thickening; vessel members with scalariform, opposite and alternate pittings, having annular, reticulate, scalariform-reticulate and pitted wall thickening, and also exhibiting transverso, oblique, simple and multi perforation plates occur to every studied species as leaflets as leaf axis. Towards ergastic matter, mucilage, starch, ellipsoidal and spherical druse-like silica-bodies were detected. Therefore, although some similarities, the analyzed species of Oenocarpus Mart. revealed important, qualitativo, anatomical-features allow their identification according as proved in the anatomical key for ones.