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Observations of hummingbird visits to bromeliads at the Cerro Jefe cloud forest, Panama
... obs.); an identical myrmecophytism to that recorded for Aechmea bracteata (Benzing 2000). Aechmea dactylina is pollinated by various hummingbird species (Pierce & Gottsberger 2001a), and although individuals may be found in flower throughout the wet season, the majority of the population appears to flower during August (S. Pierce, pers. ...
Crassulacean acid metabolism (CAM), an advanced photosynthetic pathway conferring water conservation to plants in arid habitats, has enigmatically been reported in some species restricted to extremely wet tropical forests. Of these, epiphytic Bromeliaceae may possess absorbent foliar trichomes that hinder gas-exchange when wetted, imposing further limitations on carbon dioxide (CO2) uptake. The hypothesis that the metabolic plasticity inherent to CAM confers an ecological advantage over conventional C3 plants, when constant rainfall and mist might inhibit gas-exchange was investigated. Gas-exchange, fluorometry and organic acid and mineral nutrient contents were compared for the bromeliads Aechmea dactylina (CAM) and Werauhia capitata (C3) in situ at the Cerro Jefe cloud forest, Panama (annual rainfall > 4 m). Daily carbon gain and photosynthetic nutrient use efficiencies were consistently higher for A. dactylina, due to a greater CO2 uptake period, recycling of CO2 from respiration and a dynamic response of CO2 uptake to wetting of leaf surfaces. During the dry season CAM also had water conserving and photoprotective roles. A paucity of CAM species at Cerro Jefe suggests a recent radiation of this photosynthetic pathway into the wet cloud forest, with CAM extending diversity in form and function for epiphytes.
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