Coléteres dendróides em Alibertia sessilis (Vell.) K.Schum.(Rubiaceae)
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Data
2006-02-24
Autores
Barreiro, Daniela Pacheco [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A presença de coléteres na superfície adaxial de órgãos jovens constitui uma característica relevante de Rubiaceae. Alibertia sessilis (Vell.) K. Schum., conhecida como marmelinho ou marmelo-do-cerrado, é uma espécie subarbustiva de Rubiaceae nativa de cerrado e tem grande importância alimentícia e medicinal neste bioma. Os ápices vegetativo e reprodutivo apresentam-se recobertos por uma secreção hialina, de aspecto vítreo e hidrofóbico produzida por coléteres. Neste trabalho foram investigados a distribuição, estrutura, histoquímica e o modo de secreção dos coléteres presentes em ápices vegetativos e reprodutivos desta espécie. Para estudos convencionais, as amostras foram preparadas segundo técnicas usuais em microscopia de luz e microscopia eletrônica de varredura (MEV) e transmissão (MET); técnica especial foi aplicada para dissolução da secreção e observação dos coléteres ao MEV. A técnica do ZIO foi empregada para maior visualização do sistema de endomembranas ao MET. Testes histoquímicos foram feitos em secções de material recém coletado. Coléteres nesta espécie são do tipo dendróide e ocorrem em abundância na face adaxial das estípulas, brácteas e sépalas; consistem de um eixo central multicelular e multisseriado revestido por numerosas células epidérmicas digitiformes ou pontiagudas, de tamanhos irregulares, unidas entre si somente na porção proximal e separadas umas das outras na porção distal. As células colunares são axialmente alongadas e possuem paredes espessas, núcleo conspícuo, citoplasma abundante e vacúolos desenvolvidos. As células epidérmicas possuem paredes delgadas, núcleo conspícuo, citoplasma abundante e vacuoma pouco desenvolvido. Os coléteres, de ambos os ápices, não possuem cutícula. Lipídeos, proteínas e polissacarídeos foram detectados nas células epidérmicas e colunares; compostos...
The presence of colleters in the adaxial surface of young organs constitutes a relevant characteristic of Rubiaceae. Alibertia sessilis (Vell.) K. Schum., known as marmelinho or marmelo-docerrado, is a subshrub native Rubiaceae species of cerrado and it has great nutritious and medicinal importance in this biome. The vegetative and reproductive apices present recovered for a hyaline secretion, of glass aspect and hydrophobic produced by colleters. In this work the distribution, structure, histochemistry and the way of secretion of the colleters present in vegetative and reproductive apices of this species were investigated. For conventional studies, the samples were prepared according to usual techniques in light microscopy and scanning (SEM) and transmission electron microscopy (TEM); special technique was applied for dissolution of the secretion and observation of the colleters to MEV. The technique of ZIO was used for larger visualization of the endomembranes system to MET. Histochemical assays were made in fresh material sections. Colleters in this species are of the dendroid type and occur abundantly in the adaxial surface of the stipules, bracts and sepals; they consist of a multicellular and multiseriate central axis recovered by numerous digitiform or sharp epidermal cells of irregular sizes, joined among themselves only in the proximal portion and separated from each other in the distal portion. The columnar cells are axially elongated and present thick walls, conspicuous nucleus, abundant cytoplasm and developed vacuoles. The epidermal cells present thin walls, conspicuous nucleus, abundant cytoplasm and a few developed vacuome. The coléteres, of both apices, don't present cuticle. Lipids, proteins and polysaccharides were detected in the epidermal and columnar cells; phenolic compounds were only detected in the columnar cells... (Complete abstract click electronic access below)
The presence of colleters in the adaxial surface of young organs constitutes a relevant characteristic of Rubiaceae. Alibertia sessilis (Vell.) K. Schum., known as marmelinho or marmelo-docerrado, is a subshrub native Rubiaceae species of cerrado and it has great nutritious and medicinal importance in this biome. The vegetative and reproductive apices present recovered for a hyaline secretion, of glass aspect and hydrophobic produced by colleters. In this work the distribution, structure, histochemistry and the way of secretion of the colleters present in vegetative and reproductive apices of this species were investigated. For conventional studies, the samples were prepared according to usual techniques in light microscopy and scanning (SEM) and transmission electron microscopy (TEM); special technique was applied for dissolution of the secretion and observation of the colleters to MEV. The technique of ZIO was used for larger visualization of the endomembranes system to MET. Histochemical assays were made in fresh material sections. Colleters in this species are of the dendroid type and occur abundantly in the adaxial surface of the stipules, bracts and sepals; they consist of a multicellular and multiseriate central axis recovered by numerous digitiform or sharp epidermal cells of irregular sizes, joined among themselves only in the proximal portion and separated from each other in the distal portion. The columnar cells are axially elongated and present thick walls, conspicuous nucleus, abundant cytoplasm and developed vacuoles. The epidermal cells present thin walls, conspicuous nucleus, abundant cytoplasm and a few developed vacuome. The coléteres, of both apices, don't present cuticle. Lipids, proteins and polysaccharides were detected in the epidermal and columnar cells; phenolic compounds were only detected in the columnar cells... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Botânica - Morfologia, Rubiaceae, Coléteres, Dendroid colleters, Histochemistry, Rubiaceae
Como citar
BARREIRO, Daniela Pacheco. Coléteres dendróides em Alibertia sessilis (Vell.) K.Schum.(Rubiaceae). 2006. 61 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2006.