Eficiência de diferentes métodos para superação da dormência em sementes de Dimorphandra mollis.

This work aimed to determine efficient methods for dormancy breaking in Dimorphandra mollis Benth seeds. The seeds were collected from mother trees in the municipality of Buriti, Maranhão State, Brazil. They were submitted to the following treatments: control (T1); mechanical scarification with sandpaper No. 60 (T2); chemical scarification with 98% lye (sodium hydroxide) for 15 min (T3); chemical scarification with sulfuric acid 99.9% for 20 min (T4) and thermal-shock with water (T5). In a greenhouse, we used 16 seeds per treatment, divided into four replications, in a completely randomized design. The evaluations started on the third day after seeds were treated and it was carried out until 17 days after sowing. The percentage of emerged seeds and the emergence speed index were evaluate. The mechanical scarification treatment with sandpaper (T2) and the chemical scarification with sulfuric acid (T4) were efficient to overcome the seed coat impermeability , but the mechanical scarification is the safest method for users to overcome seed dormancy. [ABSTRACT FROM AUTHOR]