Anatomia da folha e raiz da espécie Bactris gasipaes H.K.B. (Arecaceae)

Abstract

Bactris gasipaes H.B.K. (pupunha palm tree) has great economic potential, being cultivated mainly for the production of its fruits and heart-of-palm. The present work aimed to describe the anatomical structures of the leaves and roots in order to support other areas of scientific knowledge. The leaves were collected on the campus of Embrapa Amazônia Oriental, fixed in F.A.A.70% and later submitted to the usual techniques of plant anatomy. The illustrations were made in optical photomicroscopy, clear-camera drawings and Scanning Electron Microscopy (SEM). In frontal view the leaflet lamina of B. gasipaes presents: heterodimencional epidermal cells (adaxial and abaxial faces), with straight and slightly thickened anticlinal walls, coated by a smooth and waxy cuticle; amphistomatous lamina with tetracyclic stomata; non-glandular trichomes of two types: Filiform and Claviform. The transverse section of the leaf lamina shows: uniform epidermal cells, followed by hypodermis; dorsiventral mesophyll, uni or biseriate palisade parenchyma and multiseriate lacunate parenchyma, with idioblasts, raphids; central vein with collateral vascular bundles, involved by a sclerenchyma sheath. The petiole and rachis, in cross section, present: uniseriate epidermis coated by wax; filling tissue with tiny intercellular spaces, and in the petiole there are bands of elongated parenchymatic cells; collared vascular elements attached to a ring of sclerenchymatic fibers near the epidermis and dispersed in the central region. The root, in cross section, shows: thin cell epidermis, followed by tenuous hypodermis; sheath of exodermal fibers surrounding the cortex and medulla with alternating vascular elements. The species under study presented an anatomical structural configuration common to the genus described by Tomlinson (1961), but possessing characteristics peculiar to the species.