Germina??o de sementes de Dyckia tuberosa (Vell.) Beer (Bromeliaceae) sob diferentes temperaturas em luz e escuro

摘要

The effects of temperature and light on the germination of seeds of Dyckia tuberosa (Vell.) Beer, a terrestrial bromeliad from "cerrado", were studied. Seeds collected at Esta??o Ecológica of Itirapina, S?o Paulo State, were incubated at constant temperatures in the range of 10 to 45 oC, under continuous white light and darkness. The range of temperature with highest germinability under light was from 15 to 40 oC and from 20 to 40 oC in darkness, with no germination at 10 and 45 oC for light and darkness. For both, light and darkness, the optimum temperature was in the range of 30 to 35 oC. The high germinability at high temperatures shows that D. tuberosa is able to germinate in open areas and the light insensitivity of the seeds indicates that they can also germinate in conditions of completely darkness. Apparently, the germination process is not a limiting factor for this species.