Impact of accelerated aging on seed quality, seed coat physical structure and antioxidant enzyme activity of Maize (Zea mays L.)

Aging induces many deteriorative changes to seeds during storage like protein degradation, enzyme inactivation and loss of membrane integrity. In this study, we investigate the impact of accelerated aging on seed quality, seed coat physical structure and antioxidant enzyme activity of maize. Three genotypes African Tall, MAH 14-5 and a local landrace were selected and artificially aged for 96 and 120 h. The aging process led to a decrease in germination, vigour, and total dehydrogenase in seeds, while the electrical conductivity of seed leachates increased, indicating a decline in seed quality. Additionally, there was a variation in the microsculpture pattern of seed coats between genotypes. There was an accumulation of damage on the seed coat surface as the seeds aged and higher damage occurred in African Tall followed by MAH 14-5 and local landrace. Higher catalase, superoxide dismutase, peroxidase and polyphenol oxidase activity were reported in the seed coat of Local landrace and MAH 14-5 that resisted aging and deterioration while, lower catalase, superoxide dismutase, peroxidase and polyphenol oxidase activity was reported in African Tall seed coat that deteriorated during aging. Decrease antioxidant activity in aged seeds might be a possible cause of seed deterioration due to the accumulation of free radicals. Thus, these results clearly show the influence of seed coat structure and antioxidant activity on seed quality during aging.