Leaf Anatomy of <i>Prosthechea moojenii</i> (Pabst) W. E. Higgins and <i>P. silvana</i> Cath. & V. P. Castro (Orchidaceae) as an Approach to Taxonomy of Species Occurring in Biomes Cerrado and Atlantic Forest of the Bahia

Abstract

Prosthechea is a neotropical genus, belonging to the family Orchidaceae. The Brazil recorded 32 species of the genus of which nine occur in the state of Bahia, including P. silvana and P. moojenii . The first, P. silvana is epiphytic, endemic Atlantic Forest areas of South and Southeast of the Bahia and morphologically similar to P. moojenii , rupicolous species considered endemic to the Chapada Diamantina. There are doubts whether these two species are really distinct, because they differ only as to the way of life and aspects related to the size of the inflorescence and floral structure. Thus the anatomical study of these two species, emerges as a tool that aims to investigate the delimitation of these taxa. For this study, the sheet was cut freehand with a razor blade to obtain cross sections and treated by chemical means to obtain paradermic sections, all the material was stained with safranine/Astra blue (safrablau) and safranin, respectively, and the sections were then mounted between a semipermanent and cover slipped slides. The results allowed to distinguish P. silvana of the P. moojenii through the following characteristics observed in the leaf (thickening of the cell walls of epidermal cells, amount and disposition of sclerenchyma fibers and fiber arrangement of vascular and vascular bundles in the mesophyll) and root (number of arcs of xylem and phloem, thickening of cells median cortex), infers taxonomic characters for the genus. The data indicated anatomical distinction between the two species studied here of the Prosthechea , however, suggest the anatomical analysis of other organs to reproductive and vegetative.