Water uptake, priming, drying and storage effects inCassia excelsa Schrad seeds

The aims of this study were to evaluate the effects of osmotic potential on the water uptake curvein Cassia excelsa seeds and use the results to analyze the effects of dehydration and storage on primed seed germination. Seeds were imbibed in distillad water and polyethylene glicol (PEG 6000) osmotic solutions at -0.2, -0.4, and -0.6 MPa, at 20ºC. The radicle emergence and seed moisture content were evaluated at 6-hour intervals during 240 hours. Afterwards, seeds were primed in distillad water and PEG 6000 solutions at -0.2, -0.4, and -0.6 MPa for 48, 72, 96, and 168 hours at 20ºC, followed by air drying and storage for 15 days at 5ºC. The lower the osmotic potential, the higher the time required for priming. The osmoconditioning yields benefits with PEG solutions at 0.0 and -0.2 MPa; seed improvements were maintained during storage for 15 days at 5ºC, but were reverted by seed drying