Fenologia, biologia floral, mecanismo de polinização e sistema reprodutivo de duas especies simpatricas de Dichorisandra (Commelinaceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

The comparative study of phenology, floral biology, pollination mechanism and breeding system of Dichorisandra incurva e D. hexandra (Commelinaceae) was undertaken in secondary and semideciduous forest at Campinas, São Paulo, during 1989 to 1991. The species are sympatric, herbaceous, perennials and andromonoecious, with hermaphrodite and functional male flowers, clustered in cincinnus inflorescences composed of helicoid monochasium. Vegetative reproduction occurs in the two species through rhizomes. Flowers open about 0500h and wilt between 1200-1300h, lasting less than 12 hours. D. incurva is semidecidous, has a subshrub habit and plants present a clumped distribution. This species blossoms from November to April, with a flowering peak in January/February. Their flowers are zygomorpic and odorless and have a white dialipetal corollia. The anthers are yellow with a small apical introrse slit dehiscence and occupy a central position in flower around the gynoecium. In hermaphrodite flowers, the stigma protrudes beyond the anther cone, while in functional male flowers it is below and seems fade and dark. Andromonoecy is very accentuated and seems to reduce autogamy in this species, which is selfcompatible. The pollen is white and powdery, being the only resource offered to visitors. Seventeen bee species of the families Anthophoridae, Apidae and Halictidae families observed visiting D. incurva flowers and collecting pollen, mainly by buzz pollination. ... Note: The complete abstract is available with the full electronic digital thesis or dissertations

ASSUNTO(S)

fisiologia vegetal botanica anatomia vegetal

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