Watching the days go by: Aging during sunflower seed storage under distinct oxygen availability

Abstract

The maintenance of seed viability is widely studied since preserving the physiological characteristics that will allow efficient germination and adequate field occupation is broadly pursued. However, even under optimal storage conditions, the aging process is inherent to the seed’s life. In order to understand the effects of storage under low and normal oxygen conditions, this work sought to evaluate the physiological responses of two seed lots of two sunflower hybrids stored under different oxygen availability (normoxia and hypoxia) over a 360-day period. Aiming to investigate the effects of storage, the activities of the enzymatic antioxidant metabolism, hydrogen peroxide and MDA content, and the performance of viability, and vigor tests (tetrazolium test and electrolyte leakage) were performed with the stored seeds every 60 days. The hypoxia conditions were not able to keep seed viability over time, probably affecting negatively the embryonic axis. Throughout the evaluations, the viability tests demonstrated that the storage in the two experimental conditions was not able to contain the aging of the seeds. The increased content of H2O2 and MDA, associated with the enhanced electrical conductivity over time, indicate that there were losses by lipid peroxidation and that the aging process was not contained by storage under low oxygen availability.