This study examined the imbibition process and the water status of maize seed and excised embryos during seed germination. Two maize seed lots, cultivars Zeneca 8330 and 8420, were tested by germination, accelerated ageing, electrical conductivity, cold test and field seedling emergence to identify the initial physiological quality of each seed lot and to determine the relationship of the pathway of water uptake and seed quality. Seeds were hydrated between six layers of paper towel, inside a plastic box, at 25°C. Seed moisture was determined by the weighing samples of 100 seeds each and by the oven method (105 ± 3°C/24h). Seed water potential was determined by the hygrometric method through the use of a thermocouple. It was concluded that the embryo absorbs less water than the endosperm during the imbibition process. The rates of seed water uptake are related to physiological quality, as low vigour seed lot increased in moisture content faster than that of high quality. In contrast, the water potential was not affected by seed quality and cultivar. These findings suggest that the water status of seed plays a regulatory role in seed germination.
Zea mays; imbibition; water potential; physiological quality
