Imbibition of jacaranda-da-bahia seeds

Abstract

The physiological activity of the seeds begins with water uptake, resulting in tissues rehydration and triggering metabolic events of germination. In this context, the present study aimed to verify the influence of the physiological quality and initial humidity in the water absorption rate of Dalbergia nigra seeds. The seeds were collected at two different sites, representing lots I and II. Seeds belonging to the two lots were placed to hydrate in water, in desiccators with relative humidity between 95-99% at 15 oC and 25 oC, until they reached near four hydration levels: 10%, 15%, 20% and 25% of seeds moisture content. The lots were evaluated for germination, germination speed index (GSI) and mean germination time (MGT). Then, the changes in the water uptake by seeds of the two lots were evaluated after they reached the desired moisture levels, by analyzing the curves of imbibition. The experimental design was completely randomized. The lots I and II were classified as presenting high and low vigor, respectively. The results indicated that the rate of imbibition varied with initial moisture content. So the difference between the curves begins at stage II of the water absorption process. Dalbergia nigra seeds with lower physiological quality require longer periods of imbibition to reach phase III and complete the germination process.