Morfologia e ontogenese do pericarpo e da semente de Eugenia punicifolia (H. B. &K.) DC., Myrcia bella Camb. e Campomanesia pubescens (DC.) Berg (Myrtaceae) / Morphology and anatomy of the pericarp and sees of Eugenia punicifolia (H. B. &K.) DC., Myrcia bella Camb. and Campomanesia pubescens (DC.) Berg (Myrtaceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The Brazilian cerrado has been devastated and the structural aspects of the plants in this biome have been scarcely investigated considering its great diversity. In literature, there are no studies about the reproductive structures of the majority of the indigenous species of Myrtaceae, one of the most representative of the Brazilian flora and cerrados. Analyses of fruits and seeds are limited to economically important species and rarely include anatomical and ontogenetic aspects. The present work aimed at detailing and comparing the morphology and ontogenesis of the fruits and seeds of Eugenia punicifolia, Myrcia bella and Campomanesia pubescens, three species commonly found at cerrado sensu lato. Material was processed according to standard anatomical techniques for inclusion in plastic resin. In all three species, both in the ovarian wall and in the pericarp, there were a fundamental region, which was divided into three areas; a great number of cells with phenolic content; and secretory cavities with lipidic content. Ovules were campylotropous; in E. punicifolia, chalaza was extensive; in the remaining species, chalaza was less extensive. In the beginning of the fruits development, intense mitotic activity was noticed in all regions of the fruits. There were intercellular spaces in the mesocarp of E. punicifolia and M. bella as well as differentiated and isolated sclereids in the mesocarp and concrescence of the most inner layers of the mesocarp and endocarp with the seminal tegument of C. pubescens. The mesocarpic cells of mature fruits elongated radially, originating the fleshy pulp in all three species. E. punicifolia and M. bella presented very similar pericarp development; C. pubescens showed particular characteristics, following the pattern already described for its genus. During seminal development, more intense growth occurred in the anti-raphe region, originating reniform seeds. In Eugenia punicifolia, chalaza expanded, making evident the pachychalazal development of the seed. Perichalaza was formed in M. bella. In C. pubescens, chalaza expansion was restricted to the hilum. Exotesta cells elongated radially. Cell divisions increased the number of layers of mesotesta, which was phenolic all over the seminal involucrate in E. punicifolia and M. bella. The testa inner epidermis and the inner tegument did not show any alterations. The embryonic axis of E. punicifolia was short and continuous to the thick and partially concrescent cotyledons; those of M. bella and C. pubescens were very elongated. In M. bella, two twisted foliaceous cotyledons were identified. In C. pubescens, cotyledons were extremely small and could not be found anatomically. Mature seeds were campylotropous. The exotesta of Eugenia punicifolia had a lignified palisadic layer. In M. bella, ?U?-shaped thicknesses were noticed, and sclereids layers were observed in C. pubescens. Mesotestal cells of E. punicifolia showed secondary thicknesses; those of M. bella and C. pubescens did not show lignification and were tangentially compressed. In the embryo of the mature seed, differentiated phenolic idioblasts were observed as well as deposits of amid granules in all three species and subepidermic secretory cavities in E. punicifolia and M. bella. Seminal characters also followed the pattern already described for their genera

ASSUNTO(S)

plant anatomy sementes - anatomia seeds morfologia vegetal anatomia vegetal anatomy plant morphology myrtaceae pericarp

ACESSO AO ARTIGO

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