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Brazilian Journal of Botany
Print version ISSN 0100-8404On-line version ISSN 1806-9959
VOSGUERITCHIAN, Simone Bazarian and BUZATO, Silvana. Sexual reproduction of Dyckia tuberosa (Vell.) Beer (Bromeliaceae, Pitcairnioideae) and plant-animal interaction. Rev. bras. Bot. [online]. 2006, vol.29, n.3, pp.433-442. ISSN 0100-8404. http://dx.doi.org/10.1590/S0100-84042006000300010.
Bromeliaceae is an important component in several Biomas due to its remarkable ecological diversity as well as biotic interactions. It presents a combination of two reproductive mechanisms: sexual and clonal propagation. We describe in this study the various attributes related to the sexual reproduction of Dyckia tuberosa as well as plant-animal interactions that take place in its reproductive structures. In the population studied, 55% of individuals blossomed and set fruit over an 11-month period. The flowers developed from the basis to the top and had morphometrical differences with regard to its position in inflorescence that cause also differences in number of seeds set. Sugar concentration in the nectar was 20% and total production of nectar was about 24 µL flower-1 day-1. Nectar production was bigger in the morning period. Dyckia tuberosa is self-incompatible, an unusual feature for Bromeliaceae, and the index of self-incompatibility (ISI) was 0.08. Only hummingbirds were responsible for the legitimate visits of flowers, contacting anthers and stigma, and 3.9 flowers were visited per hour. Chlorostilbon aureoventris, Colibri serrirostris and Phaethornis eurynome were the hummingbird species registered. Sexual reproduction on D. tuberosa depends on hummingbirds'visitation. Inflorescences of D. tuberosa were also visited by the ant species Camponotus rufipes, Camponotus cf. mus and Cephalotes sp. As sexual reproduction is absent in many individuals and this species is dominant on the granite outcrop of Pedra Grande, we consider clonal propagation an important strategy for the spread of this species in this area. Given the presence of food resources for pollinating and non-pollinating animals on reproductive structures of D. tuberosa, this system seems suitable to assess how variation on resources availablity change the results of these interactions as well as the reproductive output of D. tuberosa.
Keywords : floral biology; hummingbird pollination; plant-ant interaction; reproductive phenology; self-incompatibility.