Biologia reprodutiva da reófita dyckia brevifolia baker (Bromeliaceae), no Rio Itajaí-Açu, Santa Catarina, Brasil

Abstract

The species Dyckia brevifolia Baker presents disjunctive populations and restricted distribution. Dyckia brevifolia is a policarpic species with clonal propagation. The reproductive biology of this species was studied on the banks of the Itajaí-Açu River, Santa Catarina, Brazil. The floral characteristics, the nectar production and the behavior of floral visitors were studied. To characterize the reproductive system, five treatments were conducted: agamospermy, spontaneous pollination, self-pollination, cross-pollination and control. Each inflorescence presented 60.4 ± 14.5 flowers and 58.3 ± 13.3 fruits and the fruit/flower ratio was 0.97. The average number of seeds per fruit was 129.6 ± 24.3. The flowers opened from the base to the apex of the inflorescence and the number of opened flowers per inflorescence and day was 6.8 ± 1.2. Flower anthesis occurs along the day and the flower lasts a day and half. The average volume and concentration of nectar was 30.5 μL and 25.7%, respectively. The main floral visitors were bees, hummingbirds and butterflies, being the hummingbird Amazilia versicolor Vieillot the main pollinator. This species also was pollinated by bees of the genera Xylocopa and Bombus. Regarding the reproductive system, the results indicate that D. brevifolia is self-compatible and that agamospermy can occur. The self-compatibility presented for this species, as well as the floral visitors' behavior indicate that the main pollination forms are self-pollination and geitonogamy.