Quebra de dormência em sementes de Hymenaea martiana e Senna spectabilis, espécies nativas da caatinga com potencial uso para restauração

Abstract

Endemic and threatened species are especially affected, unable to adapt quickly to environmental changes. Habitat fragmentation increases vulnerability to extinction by decreasing genetic diversity and connectivity between populations. On the other hand, forest restoration plays a crucial role in protecting biodiversity by recovering vegetation cover through the planting of seeds and seedlings. In this way, seeds are a critical and limited resource to restore biodiversity and ecological function of degraded and fragmented ecosystems. Understanding and considering seed dormancy and germination characteristics is essential in restoration planning, ensuring proper management and efficiency in the use of these seeds. The objective of this study was to verify the efficiency of different methods for breaking dormancy in forest species with potential use for Caatinga restoration, Jatobá (Hymenaea martiana Hayne) and Canafístula (Senna spectabilis (DC.) H.S.Irwin & Barneby). The seeds were submitted to the following treatments: control (CO), thermal scarification with immersion of the seeds in water at 80°C for 5 min (ET); chemical scarification applying concentrated sulfuric acid for 5 min (EQ); mechanical scarification with sandpaper Nº 80; (EM); and soaking in gibberellic acid (100 mg/L) for 24 h (GA). The experiments were performed in a completely randomized design with 4 replicates of 25 seeds per treatment. The observations extended for 10 days after sowing, considering as germinated those that presented the protrusion of the radicle. The germination percentage (G%) and the germination speed index (IVG) were evaluated. As a result, we found that the mechanical scarification and chemical scarification treatments stood out as the most efficient methods to overcome the impermeability of the integument in both species. By breaking dormancy provided by these treatments, these species have a greater capacity to germinate and establish themselves in the environment, contributing to the restoration of degraded areas. Therefore, the use of the mechanical scarification method is recommended, especially because it stands out as the safest option and presented a more reliable improvement of the natural germination process.