Effect of hydration and dehydration cycles on Mimosa tenuiflora seeds during germination and initial development

Discontinuity during the process of imbibition in seed germination in arid and semi-arid ecosystems produces cycles of hydration and dehydration (HD cycles). The aim of this study was to evaluate the effect of HD cycles on germination and initial growth of Mimosa tenuiflora seedlings, testing the hypothesis that seeds that pass through HD cycles produce larger seedlings with greater accumulation of biomass. Seeds of M. tenuiflora were submitted to 0, 1, 2 and 3 HD cycles. We evaluated parameters of germination and initial seedling growth. Although seed germinability did not change, M. tenuiflora seeds that were submitted to HD cycles germinated in a shorter time than seeds with continuous hydration. In addition, seedlings produced from seeds that were submitted to HD cycles had longer stems, larger stem diameter and higher leaf, stem and root dry mass values. HD cycle produced the seed hydration memory phenomenon, which may have ecological implications for the species, since the seeds that underwent HD cycles produced more vigorous seedlings.