Changes in seed hydration memory expression through different seasons in a Seasonally Dry Tropical Forest

Abstract

Abstract In Seasonally Dry Tropical Forests, seeds are naturally submitted to hydration and dehydration cycles (HD cycles) during germination process, which can promote the seed hydration memory expression. We investigated how seeds from the same population produced and dispersed in different seasons of the year express seed hydration memory under water deficit conditions after discontinuous hydration, at different hydration times. We collected seeds produced during the dry season and dispersed at the beginning of the rainy season and seeds produced during the rainy season and dispersed at the beginning of the dry season. Seeds were submitted to 0, 1, 2 and 3 HD cycles with different hydration times and placed to germinate under ideal conditions. After verifying that the hydration time between cycles did not influence germination response of the studied species, seeds collected in both seasons of the year were submitted to 0, 1, 2 and 3 HD cycles and placed to germinate at different osmotic potentials (0.0, -0.1, -0.3, -0.6 and -0.9 MPa). After evaluating the germinal parameters, we observed that (1) seeds from the same population, produced and dispersed in different seasons, express seed hydration memory in a different way during their germination process and (2) discontinuous hydration confers greater acquisition of tolerance to seeds produced during dry season. Such germinal responses to HD cycles characterize the seed hydration memory expression, which is influenced by the environmental conditions present during seed development and post-dispersion, conferring ecological implications on the reproductive success of the species.