ROS production and lipid catabolism in desiccating Shorea robusta seeds during aging

Abstract

Reactive oxygen species (ROS) and lipid peroxidation products appear to correlate strongly with the desiccation induced loss of viability in recalcitrant sal seeds. The 100% germination in fresh sal seeds declined with dehydration under natural storage conditions (26 ± 1 °C, relative humidity 52 ± 2%). Seeds became non-viable within 8 days. Desiccation induced disturbances in the metabolic activity of seeds resulted in generation of enormous amounts of ROS that are responsible for cellular damage and viability loss. Oxidative stress in the dehydrating aging sal seeds was further aggravated by inducing lipid peroxidation as the amounts of free fatty acid, conjugated diene, lipid hydroperoxide and secondary free radicals; malondialdehyde and 4-hydroxy-2-nonenal, were also promoted. In addition, significant rise in lipid degrading enzymes; lipase (EC 3.1.1.3) and lipoxygenase (LOX, EC 1.13.11.12) were detected in dehydrating sal seeds. Our results indicated multiple pathways (ROS, lipid peroxidation & lipase and LOX) that operate in the dehydrating recalcitrant sal seeds finally contributing to loss of viability.