Physiological and oxidative changes during the storage of Moringa oleifera Lam. seeds
Antioxidant enzymes; Hydrogen peroxide; Lipid peroxidation; Non-enzymatic antioxidants; Seed deterioration.
Oxidative damage plays a central role in seed deterioration during storage. Thus, the current work aimed to characterize viability and vigor as well as oxidative damage and protection during the storage of Moringa oleifera Lam. (moringa) seeds. Seeds were kept in plastic bags and stored in a growth chamber (27 ± 2°C and RH 65%) and under refrigeration (4 ± 2°C and RH 25%) for twelve months. Samples were collected after havest and every three months during storage, evaluating water content, germination percentage, first count, germination speed index, percentage of abnormal seedlings, lipid peroxidation, H2O2 content, total, reduced and oxidized ascorbate content, as the activity of superoxide dismutase, ascorbate peroxidase and phenol peroxidase. In the seeds stored in the growth chamber, there was an increase in water content and percentage of abnormal seedlings after twelve months of storage in parallel with a decrease in germination percentage, first count and germination speed index, compared with the refrigerated environment. Regardless the environment, moringa seeds did not show an increase in lipid peroxidation, but there was a decrease in H2O2 content, coinciding with an increase in reduced ascorbate content and superoxide dismutase and ascorbate peroxidase activities. Thus, the refrigerated environment is more suitable for the storage of moringa seeds compared with the growth chamber, taking into account the changes in water content, viability, and vigor of seeds. However, these changes can not be attributed to lipid peroxidation during the experimental period. Instead of this, the decrease of H2O2 content over time may be related to oxidative protection supported by reduced ascorbate, superoxide dismutase and ascorbate peroxidase.