Machado et al. 2015 (Conference Paper) Vriesea, leaf

Trying to understand Vriesea taxonomy with leaf anatomy

Author(s):—T.M. Machado, F. Vale, L. Versieux & J.R. Stehmann in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution

Publication:— (2015).

Abstract:—Vriesea is the largest Bromeliaceae genus in Brazil, with 208 endemic species in this country. The Atlantic Rainforest is a center of diversity for the genus, but the Espinhaço Mountain Range is also an important region for presenting many endemic species. Due to the heterogeneity of environments occupied by Vriesea species and the great morphological diversification developed in the occupation of these environments, the taxonomy of the genus has problems. The aim of this study is to describe the leaf anatomy of 14 species of the genus that occur in different environments and substrates and discuss the taxonomic and ecological implications of the observed features. Samples were taken from the middle of the leaf blade and fixed in FAA 50% and then preserved in 70% alcohol. Freehand cuts were made and the material was stained with safranin and astra blue and then mounted in glycerin. The general characteristics for the genus were: hypostomatic leaves with stomata on the same plane as the other epidermal cells and stomata connected to air channels, uniseriate epidermis with the presence of scales on both sides, lignified hypodermis and groups of subepidermal fibers; parenchyma consisting of three cell types: the braciformes that are found forming the aerenchyma of air channels, isodiametrical clorophyllian surrounding the air channel, especially in the adaxial side forming alternating arcs with vascular bundles and isodiametrical with respect to water storage tissue. Species that occupied the same type of environment as rocky fields and high altitude grassland had similar anatomy, but can be differentiated by variations in the distribution and density of stomata and scales, variation in the shape of the air channels and height of the aquiferous parenchyma. Vriesea appariciana was the species with the highest variation in the general aspect, showing adaptation to extreme environments suc as inselbergs or conservation of ancestral characteristics. Anatomy was shown to provide important characters that can be used in taxonomy and systematics of Vriesea and allow a better understanding of the environments occupied by the species.

Keywords:—Rupiculous; Adaptation; Evolution.