Biologia reprodutiva de Guettarda platypoda DC. (Rubiaceae) em uma área de restinga no Estado de Pernambuco

• Autor(a) principal: NOVO, Reinaldo Rodrigo
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/4928
• topic: Biologia reprodutiva; Guettarda; Heterostilia; Sistema reprodutivo; Polinização; Distilia; Rubiaceae; Reproductive biology; Reproductive system; Pollination; Distyly; CIENCIAS BIOLOGICAS::BOTANICA

Distyly is a syndrome mainly found in the Rubiaceae family, being characterized by a floral dimorphism in which some individuals have thrum flowers (T) and others have pin ones (P). Typical distylous species present reciprocal hercogamy between floral morphs, a self and intramorph incompatibility mechanism and an equilibrated proportion of morphs in the population (isoplethy). Selective pressures such as the reproductive isolation or deficient pollination services may result in the break down of the distylous syndrome, and consequently in modifications on morphological and reproductive patterns of species of typically distylous groups. This study investigated the floral biology, the breeding system, the pollination and the floral morphometric relations of Guettarda platypoda DC. (Rubiaceae) in an area of coastal vegetation in the Pernambuco state, using measurement of floral parts, hand pollination experiments, estimate of floral morphs ratio in the population and focal observation of floral visitors. Guettarda platypoda have hermaphrodite, tubular, nectariferous flowers that produce a sweet odor; anthesis is nocturnal and flowers are pollinated by mophs and sphingids. Morphometric data showed the absence of reciprocity between the floral morphs, a feature that may limit distyly function. Both floral morphs produced fruits after all hand pollination experiments, and the species may be considered self and intramorph compatible. Because of these features, the species is considered as atypically distylous. Both the morphological and the compatibility conditions recorded here may be related to the break down of the distylous syndrome, which may be occurred because of deficient pollination services and/or habitat fragmentation, since the study area is strongly altered by antropogenic occupation. More specific genetical studies must be developed to investigate the distyly supergene integrity in the genus, since other studiesshowed similar morphological variations in other regions, some of them also related to pollination services.