Orchidaceae do Parque Estadual da Serra de Caldas Novas, Goiás, Brasil
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Data
2009-03-31
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Universidade Federal de Goiás
Resumo
(Orchidaceae of the State Park of Serra de Caldas Novas, Goiás State, Brazil). This study conducted a survey of the Orchidaceae species occurring at State Park of Serra de Caldas Novas (PESCAN) and a study of the floral biology and reproductive biology of Cyrtopodium eugenii Rchb. f. & Warm. and the effect of floral herbivory on reproductive success of this specie that occurs in the rocky fields of PESCAN. The Orchidaceae family consists of 850 genera, with about 20000 species, and has cosmopolitan distribution, but its greatest concentration is in the tropical region. In Brazil, 200 genera are found, with more than 2500 species, and then, it is considered the third country in the world in diversity of orchids, only inferior to Ecuador and Colombia. In the Cerrado Biome, the family is represented by 666 species, from these, 12 species and 7 genera were found in PESCAN. The most common habit among the species that occur in PESCAN is the terrestrial and the predominant flowering season is the rainy season. Only one specie flowers in the dry season, C. eugenii, a common specie in PESCAN, which flowers from May to September. Cyrtopodium eugenii flowers are pale-yellow with brown spots, but the lip is bright-yellow. The only species found as a pollinator of C. eugenii was Centris (Trachina) fuscata Lepeletier,1841 (Anthophoridae, Centridini). Although C. eugenii offers no floral rewards to pollinators, its lip seems to mimic flowers of Tetrapterys ramiflora A. Juss., a yellow-flowered oil producer Malpighiaceae. Thereby, C. eugenii deceives the pollinator. As in other species without reward, C. eugenii receives few visits from their pollinator, and consequently has a low fruit production rate. Cyrtopodium eugenii is self-compatible, but no fruit was generated by spontaneous self-pollination as well as agamospermy. Preliminary field observations revealed that inflorescences and flowers of C. eugenii experience continuous florivory. The natural florivory quantification shows that 55.20% of the flowers weren t eaten,while in 15.45% sexual structures were eaten (florivory direct effect). More flowers had the lip damaged (20.50%) than the other petals and sepals (18.92%). A manipulative experiment showed a significant decrease in C. eugenii reproductive success (male and female), only if the florivory occurred in the lip (florivory indirect effects). This result indicates that the lip is the most important flower part to attract the pollinator and to C. eugenii reproduction, because even with a high level of herbivory in the other petals and sepals, the reproductive success didn t decay significantly.
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HALL, Climbiê Ferreira. Orchidaceae of the State Park of Serra de Caldas Novas, Goiás State, Brazil. 2009. 85 f. Dissertação (Mestrado em Ciências Biológicas - Biologia) - Universidade Federal de Goiás, Goiânia, 2009.