Physiological Potential, Storage and Enzyme Activity of Corn Hybrid Seeds.

Corn (Zea mays L.) has great potential for production of seeds with high physiological potential, given its morphological and chemical constitution and the advent of the hybrid corn. However, during the production process, especially harvesting, drying and storage, seeds may be altered, such as changes in the activity of cells antioxidant systems. Thus, this research aimed to study the relationship between physiological potential, storage and activity of free radical-scavenging enzymes of corn hybrid seeds from different crop seasons. Seeds of four corn hybrids, crop year 2009/10, 2010/11, 2011/11 and 2011/12 were evaluated by germination, vigor (cold test, accelerated aging and electrical conductivity) and seedling emergence in the field tests. The activity of superoxide dismutase, catalase and esterase was determined by electrophoresis, using seedling hypocotyls, after five days of germination. The results of germination and cold test did not show significant differences of physiological potential among the seed lots. Accelerated aging and electrical conductivity tests were able to differentiate hybrids from different crop years and those stored for longer periods showed lower seed performance compared to the recently harvested. The evaluation of the electrophoretic patterns of superoxide dismutase and catalase enzymes did not enable to identify differences among hybrids. Enzymatic profile of esterase showed variation among hybrids, however, the results were not consistent as expected, since the lowest activity of this enzyme was observed for seeds harvested in 2011/11, which remained stored for relatively short period. Thus, the vigor tests allowed the characterization of corn hybrids from different crops, although, it was not possible to relate it to the activity of free radical-scavenging enzymes.