Anatomical, Histochemical and Cytogenetic Features of Doryopteris triphylla (Pteridaceae)

Abstract

Doryopteris triphylla (Pteridaceae-Cheilanthoideae) grows in xeric habitats inBrazil, Paraguay, Uruguay and Argentina. The aim of this study was to characterizeD. triphylla anatomically, histochemically and cytogenetically. Foranatomical characterization, rhizomes, roots, petioles and leaves were madeand then stained using Safranine-Astra Blue for further observations. Leafblades were also cleared. For histochemical analysis, leaf cross sections werestained with different reagents to identify glandular trichomes compounds.For cytogenetic characterization, a karyogram was performed using laboratorycultivated roots. Results show a dictyostelic rhizome covered with scales withapical secreting gland; diarch roots; petiole cross-sections show thick cuticle,uniseriate epidermis, parenchymatic cortex cells with thick walls and a vascularbundle with two xylem groups; and hypostomatic fronds with glandulartrichomes. Histochemical studies of secretion products of the glandular trichomeswere positive for polysaccharides, pectins, lipids, acid lipids, dihydroxyphenols,phenols and flavonoids. Cytogenetically, D. triphylla is describedas a diploid species (2n = 60), with chromosomes gradually decreasingin size. The apical glands in scales of rhizomes, the presence of two xylemgroups in the vascular bundle in the petiole and the glandular trichomes onthe abaxial surface are new contributions to the species. The type of chemicalproducts secreted by glandular leaf trichomes and karyotype estimation isshown for the first time in this species.