Desenvolvimento floral e expressão sexual em espécies de Ficus L. (Moraceae) / Floral development and sex expression in species of Ficus L. (Moraceae)

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

18/02/2011

RESUMO

The absence of reproductive organs in some flowers may ontogenetically arise by organ loss or suppression. Ficus L. is an interesting model for floral developmental studies, due to its diversity in sexual systems. The aim of this study was to compare the morphology of the floral development in Ficus citrifolia (monoecious), F. hispida (gynodioecious), F. racemosa (secondary monoecious) and F. religiosa (monoecious), to help understanding the ontogenetic pathways that promote the condition "imperfect flower". Thus, figs at various developmental stages were collected, fixed in FAA 50 and prepared for surface (scanning electron microscopy) and histological observations (light microscopy). The organization of the floral meristem and flowers inside the syconium is quite compressed, although F. hispida (gynodioecious) exhibits a less compressed floral arrangement inside the syconium. Variation in meristem inception time and pedicel elongation were observed in carpellate flowers of monoecious species (F. citrifolia, F. racemosa and F. religiosa) and should be crucial for establishment of incomplete heterostyly. The carpellate flowers of all species showed a sinstigma in the later developmental stages (except the gall-producing syconium in F. hispida). The staminate flowers of F. hispida showed carpel suppression. Our data, compared with those in the literature, indicate that the absence of stamens in carpellate flowers is due to loss of stamen primordium, both in gynodioecious and monoecious species. This condition is present in the genus and in Moraceae as a whole, while the carpel primordium may be lost or suppressed in this group. Aspects of floral development observed in Ficus are discussed in relation to their systematic and reproductive biology

ASSUNTO(S)

ginodioicia ficus (botanica) ontogenia monoicia gynodioecy ficus (botanicals) floral ontogeny monoecy sexual systems

ACESSO AO ARTIGO

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