Guazuma ulmifolia Lam. have seed with high water impermeability which impairs germination. The effect of the immersion time (0, 4, 8, 12 and 16 minutes) of Guazuma ulmifolia Lam. in concentrated sulfuric acid, and water at 60ºC for 0, 4, 8, 12 and 16 minutes were evaluated for emergency and vigor (start of the emergency and speed index). The experiment was carried out in the Biology Laboratory, in a completely randomized design in 2 x 5 factorial (2 pre-emergency treatment and 5 immersion times), with three replicates of the 20 seeds. The pre-conditioning of seeds in sulphuric acid as well as in water at 60ºC was efficient in breaking the seed dormancy and also for increasing the emergence percentage and speed, and reduction of the time for onset of emergence. The efficiency of this chemical treatment with sulphuric acid was obtained with a immersion time of 8 minutes, while in the physical treatment with water at 60ºC, the efficiency was obtained with immersion time of 16 minutes.
Dormancy; Germination; Scarification
