Physiological potential of sorghum seeds under discontinuous hydration and water deficiency conditions

Abstract

Hydration and dehydration cycles during imbibition of seeds may influence their physiological performance, making them more vigorous and resistant to abiotic factors such as water stress. The aim of this study was to investigate whether sorghum has water memory and to evaluate whether discontinuous hydration cycles condition greater resistance to water deficiency in seed germination and vigor. The experiment was carried out in a randomized experimental design with four replicates of 50 seeds. The treatments were arranged in a 3 x 4 x 6 factorial scheme (hydration times, hydration and dehydration cycles, osmotic potentials). The imbibition curve of the species was determined based on three times (X, Y and Z); and the dehydration curve was constructed. With these times, the seeds were submitted to 0, 1, 2 and 3 cycles of hydration and dehydration (HD). Then, they were submitted to germination test on paper moistened with polyethylene glycol 6000 solution at the osmotic potentials of 0.0 (distilled water), -0.2, -0.4, -0.6, -0.8 and -1.0 MPa. Sorghum seeds have water memory, but the HD cycles did not influence germination. Their germination and vigor are affected from the potential of -0.2 MPa. At this potential, the increase of the cycles led to greater vigor and accumulation of the organic compounds.