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Reproductive biology and pollination in Epidendrum paniculatum Ruiz & Pavón (Orchidaceae)

Epidendrum paniculatum Ruiz & Pavón occurs in Central and South America. The populations studied grows on rocks of semidecidual forests at the Serra do Japi (São Paulo State - Brazil). The flowers are green and white, and fragrant during the day and the night. In the study area, the pollinators are Ithomiinae butterflies and diurnal moths of the family Arctiidae, both reported to collect alkaloids of certain flowers. The tests performed revealed, however, that alkaloids are not present in flowers of E. paniculatum. The pollinators are attracted by the flowers of this species probably due to fragrance and nectar production. The treatments carried out revealed a high level of self-incompatibility within the flowers of E. paniculatum. Due to the tendency of many Lepidoptera to remain at specific micro-habitats, the occurrence of self-pollination is very common. The high level of self-incompatibility, combined with pollinator inefficiency, promotes a strong loss of pollen and consequently low fruit set. The small number of fruits produced is derived from cross-pollination. This fact plus to the production of thousands of seeds dispersed by wind in each fruit, probably is sufficient to maintain of the number individuals constant in the region, genetic variation, and extensive distribution of E. paniculatum.

Epidendrum; Orchidaceae; pirrolizidine alkaloid; pollination; reproductive biology


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