Superação de dormência em sementes de Libidibia férrea (MART. EX TUL.) L. P. Queiroz var. ferrea (Fabaceae).

Abstract

Libidibia ferrea (Mart. Ex Tul.) L.P. Queiroz var. ferrea, popularly known as "pau-ferro" or "jucá", is a tree species native to Brazil found in the Caatinga. Its seeds have a tegument of the type impermeable to water, which causes integumentary dormancy and makes the germination process difficult. Thus, the objective of this work was to evaluate different pregermination methods to overcome dormancy in L. ferrea seeds. The treatments were: T0 control, T1chemical scarification in sulfuric acid(H2SO4) for 20 minutes, T2 chiselling in H2SO4 for 40 minutes; T3mechanical scarification with sandpaper No. 80, T4-Mariabath at 100 ° C for 15 minutes, T5 Maria bath at 80 ° C for 15 minutes and T6 immersion in alcohol vinegar for 15 minutes. The evaluated parameters were germination speed index, first count and final percentage of germination, shoot height, root length, fresh and dry mass of seedlings. The experimental design was completely randomized with four replicates of 25 seeds for each treatment, and the samples were kept in a germination chamber at 30º C for 15 days. The analysis of variance indicated a significant difference between the treatments in all evaluated parameters. The highest averages for all variables were observed from the chemical scarification with H2SO4 for 20 minutes and 40 minutes, which did notdiffer statistically from each other by the Tukey test at 5%. On the other hand, the treatments with alcohol vinegar for 15 minutes and control were the least effective. Therefore, it is concluded that the chemical scarification with sulfuric acid for 20 minutes is the most appropriate treatment for overcoming dormancy in L. ferrea seeds