Reserve mobilization and seedling development of common bean seeds pre-soaked in gibberellic acid

Abstract

Soaking of seeds with gibberellin can alter seedling performance, as it can directly affect reserve mobilization and vigorous seedling formation. The objective of this study was to evaluate whether common bean seeds with contrasting vigors alter reserve mobilization and seedling development after supply of different doses of exogenous gibberellic acid (GA₃). The experimental design was completely randomized, in a 2x5 factorial arrangement (two cultivars and five GA₃ concentrations). The cultivars BAF55 and BAF44 showed contrasting vigors, being characterized as high and low vigor, respectively. The parameters evaluated showed interaction between cultivar and dose, which demonstrates genetic variability regarding sensitivity to the hormone. The cultivar BAF55 had mobilization of reserves impaired by the increase of GA₃ doses, having a higher remaining dry mass in the cotyledons, this demonstrates that the reserves were not used during seedling development, resulting in lower dry mass. On the other hand, in the BAF44 cultivar, the increase in hormone doses favored the use of seed reserves, promoting greater seedling length. Doses up to 0.10 mM L^-1 of GA₃ provided longer hypocotyl, epicotyl and seedling lengths, in addition to reducing cotyledon mass. This demonstrates the use of the reserves previously synthesized in the cotyledon. Therefore, the application of the hormone in the seed directly influences the architecture of the seedling, but it enhances the use of cotyledon reserves for the BAF44 cultivar in a more efficient way, forming more vigorous seedlings with greater length and dry mass.