Polimorfismo floral em Valeriana scandens L. (Valerianaceae)
Data
2010-09-01
Autores
Duarte-Silva, Erica
Vieira, Milene Faria
Bittencourt Jr, Nelson Sabino [UNESP]
Garcia, Flávia Cristina Pinto
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Botânica do Brasil
Resumo
Foram encontrados três morfos florais em Valeriana scandens L.: flor perfeita, flor pistilada 1 e flor pistilada 2. A perfeita possui corola maior que a dos demais morfos, com lobos reflexos na antese, giba proeminente e localizada na porção proximal do tubo floral; anteras maiores que as dos demais morfos, com pólen viável; estilete curto e estigma incluso, o menor ovário e saco embrionário estruturalmente normal, semelhante ao dos demais morfos. A pistilada 1 possui a giba menos proeminente, corola de tamanho intermediário em relação aos demais morfos, lobos radiais na antese; anteras pequenas, sem pólen e estilete longo e estigma exserto. A pistilada 2 possui lobos radiais na antese, anteras de comprimento semelhante às da perfeita, mas de menor largura, com pólen inviável; estilete mais curto, tal como o da flor perfeita, e estigma exserto, tal como o da flor pistilada 1. Nos três morfos, o nectário é formado por tricomas secretores unicelulares situados na epiderme da face interna da giba, e suas sementes são viáveis. As flores pistilada 2 e perfeita apresentam um septo que isola a giba do restante do tubo floral, formando uma câmara nectarífera. V. scandens L. é ginomonóica-ginodióica, expressão sexual inédita em Valerianaceae.
Three floral morphs were found in Valeriana scandens L.: perfect, pistillate 1, and pistillate 2. In perfect flowers, the corolla is longer than in the other morphs, with reflexed lobes at anthesis and a prominent gibbus at the tube base; anthers are longer and contain viable pollen grains; the pistil has a short included style/stigma and the smallest ovary, but a structurally normal embryo sac similar to that of the other morphs. In pistillate 1 flowers, the corolla is intermediate in size, and has radially displayed lobes at anthesis, and a softly prominent gibbus; anthers are small and devoid of pollen; the pistil shows a long exerted style/stigma. In pistillate 2 flowers, the corolla also has radially displayed lobes; anthers are similar in length to the perfect flower, but narrower, and contain nonviable pollen grains; the style/stigma is as short as in perfect flowers, and is exerted as in pistillate 1 flowers. The three morphs produce viable seeds, and have a nectary formed by single-celled trichomes located on the inner face of the gibbus. Pistillate 2 and perfect flowers have a septum that isolates the gibbus from the rest of the corolla tube, forming a nectariferous chamber. The gynomonoecious-gynodioecious sexual expression verified in V. scandens L. is a novelty for Valerianaceae.
Three floral morphs were found in Valeriana scandens L.: perfect, pistillate 1, and pistillate 2. In perfect flowers, the corolla is longer than in the other morphs, with reflexed lobes at anthesis and a prominent gibbus at the tube base; anthers are longer and contain viable pollen grains; the pistil has a short included style/stigma and the smallest ovary, but a structurally normal embryo sac similar to that of the other morphs. In pistillate 1 flowers, the corolla is intermediate in size, and has radially displayed lobes at anthesis, and a softly prominent gibbus; anthers are small and devoid of pollen; the pistil shows a long exerted style/stigma. In pistillate 2 flowers, the corolla also has radially displayed lobes; anthers are similar in length to the perfect flower, but narrower, and contain nonviable pollen grains; the style/stigma is as short as in perfect flowers, and is exerted as in pistillate 1 flowers. The three morphs produce viable seeds, and have a nectary formed by single-celled trichomes located on the inner face of the gibbus. Pistillate 2 and perfect flowers have a septum that isolates the gibbus from the rest of the corolla tube, forming a nectariferous chamber. The gynomonoecious-gynodioecious sexual expression verified in V. scandens L. is a novelty for Valerianaceae.
Descrição
Palavras-chave
esterilidade masculina, ginomonoicia-ginodioicia, nectário floral, polimorfismo estilar, floral nectary, gynomonoecy-gynodioecy, male sterility, stylar polymorphism
Como citar
Acta Botanica Brasilica. Sociedade Botânica do Brasil, v. 24, n. 3, p. 871-876, 2010.