Germinação de sementes de umbu (Spondias tuberosa) com escarificação mecânica e embebição em água

Abstract

Optimizing the propagation of the umbu tree (Spondias tuberosa) is crucial for the socioeconomic development of communities in the Caatinga region. This species, which holds high cultural relevance and is endemic to the semi-arid environment, exhibits strong seed coat dormancy, creating obstacles to seedling production. However, there is a lack of efficient methodologies to overcome this dormancy, hindering its management and cultivation. Thus, the objective of this study was to evaluate the effect of different soaking times in distilled water, after mechanical scarification, on the germination of umbu tree seeds. The evaluation of mechanical scarification and soaking was conducted with four treatments: T1 (mechanical scarification), T2 (scarification + 12 h soaking), T3 (scarification + 24 h soaking), and T4 (scarification + 48 h soaking), in a completely randomized design with four replications of 25 seeds each. Physiological variables (percentage, MGT, MVG, GSI, synchrony, uncertainty) and morphological variables (root and shoot length, and seedling dry mass) were analyzed. Data were subjected to analysis of variance, with means compared by Tukey’s test at 1% and 5% probability levels, and regression analysis for quantitative variables. Mechanical scarification alone resulted in the highest germination percentage (77.00%), statistically superior to treatments with prolonged soaking, which showed a progressive reduction in germination (60.00% in T2; 37.00% in T3; 35.00% in T4). The other variables showed no significant differences among treatments. The results demonstrate that mechanical scarification is sufficient to overcome umbu tree seed dormancy, while prolonged soaking tends to impair seed viability.