The role of high temperatures in overcoming seed dormancy of Ormosia arborea (Vell.) Harms (Fabaeae)

Abstract

Fire, a common factor in the Cerrado, can contribute to overcoming physical numbness in seeds of some species. Thus, the objective of this study was to evaluate the effect of high temperatures, simulating fire, on the germination of Ormosia arborea seeds, a native cerrado species that presents integument dormancy. The seeds were submitted to temperatures of 25 ° C, 90 ° C, 120 ° C and 150 ° C for 5 minutes, after which one batch was subjected to chemical scarification with sulfuric acid and the other kept without chemical treatment. It was verified that exposure to temperatures up to 150 ° C was not sufficient to overcome dormancy of the species, on the other hand, the association of heating with scarification enhanced the germination when the seeds were exposed at 90 ° C and damaged seed embryos submitted to temperatures ≥ 120 ° C, indicating that the heat treatment may have initiated small cracks in the rigid and impermeable tegument.