Desempenho germinativo de Cochlospermum regium sob diferentes métodos de superação de dormência tegumentar

Seed coat dormancy represents the main obstacle to the controlled propagation of Cochlospermum regium (Mart. ex Schrank) Pilg., a native tree species of the Brazilian Cerrado with ecological and medicinal relevance. This study aimed to evaluate the efficiency of different dormancy-breaking methods on the germination and the germination speed of C. regium seeds. The experiment was conducted in a completely randomized design with six replications of 50 seeds each, totaling nine treatments: mechanical scarification in a rotary drum with sandpaper grits of 100, 150, and 220 for 60 minutes; chemical scarification by immersion in concentrated sulfuric acid for ten, thirty, and ninety minutes; immersion in hot water at 88°C for five minutes; immersion in hot water until cooling to room temperature; and an untreated control. Germination percentage, germination speed index, and cumulative germination curves were evaluated over 21 days. Mechanical scarification with 100-grit sandpaper and chemical scarification for ninety minutes yielded the highest germination and germination speed values, significantly outperforming all other treatments. Thermal treatments did not differ statistically from the untreated control, demonstrating their ineffectiveness in overcoming seed coat dormancy in C. regium. It is concluded that dormancy in this species is predominantly physical in nature and responds selectively to mechanical and chemical scarification methods. Mechanical scarification with 100-grit sandpaper is recommended for use in nurseries and Cerrado ecological restoration programs, as it eliminates the need for corrosive reagents without compromising germination efficiency.