Acta Botanica Brasilica
versão impressa ISSN 0102-3306
GALASTRI, Natália Arias e OLIVEIRA, Denise Maria Trombert de. Morphology, anatomy and ontogeny of the fruit and seed of Vernonia platensis (Spreng.) Less. (Asteraceae). Acta Bot. Bras. [online]. 2010, vol.24, n.1, pp.73-83. ISSN 0102-3306. http://dx.doi.org/10.1590/S0102-33062010000100008.
The Asteraceae comprises approximately 23,000 species and Vernonieae is best represented in Brazil; Vernonia is the largest genus in this tribe. Due to occurrence in extensive areas of Cerrado, Vernonia platensis was selected for this work that aims to describe the morphology, anatomy and development of the pericarp and seed of this species, comparing the results with the literature. The collected material was processed by conventional techniques. The ovary is inferior, bicarpellate, syncarpous, unilocular with a single anatropous ovule, unitegmic, tenuinucelate, attached in a basal placenta. The ovary wall is homogenous with dense cells peripherally. The integument has three zones, with a conspicuous endothelium. At maturity, most layers collapse, only the outer mesocarp fibers remaining; the double pappus persists and has lignified cells. The mature seed has a testa composed of collapsed cells; the endosperm is cellular, residual at maturity, and the embryo has a thick, short, and axial embryo axis. Completely developed seeds were found in only 40% of the mature cypselae evaluated. Our observations corroborate previous research with Asteraceae; we call attention to the nutritive role of the seed coat in seed development, and the low production of seeds in V. platensis.
Palavras-chave : anatomy; development; morphology; pericarp; seed coat.