Martins et al. 2015 (Conference Paper) Dyckia

Morphological characterization of the ovarian wall, stigma, stylus and ovules in two species of Dyckia (Bromeliaceae)

Author(s):—M. Martins, M. Dorneles, J.M. Oliveira & F. Nicoloso in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—The complexity and large structural variability of the carpel, stigma, style and ovule, make such characters very importantin morphological, taxonomic and phylogenetic analyses. The number of undetermined species or inaccurate identifications of Dyckia species is considered high, due to a lack of consistent and useful taxonomic characters. The objective ofthe present work is to comparatively describe the ovary wall, style, stigma and ovule by histology and light microscopyin Dyckia racinae L.B.Sm. and Dyckia polycladus L.B.Sm. in order to increase knowledge of the species and familyand see if the characters studied are consistent. Flowers at various stages of development were collected in São Pedro doSul, and Santa Maria, RS, Brazil. For the structural analysis, the usual plant microthecniques and light microscopy wereperformed. D. polycladus and D. racinae have perfect, trimerous, heterochlamidous flowers, surrounded by a bract. D. racinae presents larger flowers. The ovary is superior and syncarpous, trilocular, plurispermic. The stigma is the spiral,conduplicate type, with three carpels unfused along their margins, separate and spiraling together. In D. racinae the styleis long, with a length approximately twice the ovarian length, differing from D. polycladus. In both species, the ovules are anatropous. The ovule in D. racinae presents provascular tissue in the outer integument, unlike D. polycladus. The inner integument of D. racinaeis longer than the outer integument, while in D.polycladus they are the same length. D.polycladus presents an outer integument with intercellular spaces in the upper part, differing from D. racinae. D. racinae, which have a chalazal appendix developed from cells recruited from dorsal and ventral region in the chalaza. In D. polycladus, thechalazal appendix cells are recruited only from the dorsal region, including the funiculus. Among the characters presentedhere for Dyckia racinae and D. polycladus, the most informative are: ovarian size relative to the style, vascularization ofthe outer integument, chalazal appendix position, and integument length. Thus, the morphological analysis of the ovulesshows differences between taxa. It is believed that the expansion of studies, with emphasis on the ovules can contribute tothe understanding Dyckia and Bromeliaceae phylogeny.

Keywords:—Bromeliaceae; Dyckia Polycladus; Dyckia Racinae.