The Seed Water Sorption Isotherm and Antioxidant-Defensive Mechanisms of Hordeum vulgare L. Primed Seeds

The key successful for seed priming technique was the management of seed imbibition process. This study was aimed to indicate the seed moisture sorption characteristics of Hordeum vulgare L. cv. Samerng 2 in relation to the seed priming technique and its effect on the seed qualities. The experiment was designed by Completely Randomized Design (CRD) with four replications. Seed hydro-priming technique was done under 25 degree Celsius, and 40% - 60% RH. Barley seed moisture content was determined every hour after imbibition for 24 hours. Then, primed barley seed qualities were evaluated at 6, 8, 10, 12, 14, and 16 hours of hydrotime. The results revealed that barley seeds were imbibed rapidly from 10.55% to 37.69% seed moisture content during 0 - 9 hours of imbibition. The constantly seed moisture content was continued until 17 hours of imbibition. Radicle was protruded with 42.74% seed moisture content. Seed moisture sorption characteristic equation was Y = 0.0055x3- 0.267x2 + 4.5931x + 13.348. Coefficient of determination (R2) was 0.916. Primed seed germination was not affected by hydrotime. Primed seeds were improved in speed of germination and seedling growth rate. The best primed barley seed vigorous was noted at 14 - 16 hours of hydrotime. In addition, catalase activity (CAT) and superoxide dismutase activity (SOD) were not significantly different for non-primed and 14 - 16 hours primed seeds. However, lipoxygenase activity (LOX) was increased and malondialdehyde (MDA) content was decreased for 14 - 16 hours primed seeds. Subsequently, 14 - 16 hours primed barley seeds can maintain high seed germination and vigor for 8 - 12 months under 5 degree Celsius. Thus, it could be concluded that hydro-priming for 14 - 16 hours enhances barley seed quality by reducing germination time, induced defenses mechanism, and could be stored for 8 - 12 months.