Membrane deterioration and other biochemical changes, associated with accelerated ageing of maize seeds

Abstract

Different biochemical assays were conducted to investigate the changes occurring during accelerated ageing of maize seeds. Decreases in the level of phospholipids and ascorbate and in the activity of peroxidase and increases in the activity of phospholipase A, the level of total free fatty acids and malonaldehyde, along with the formation of conjugated lipids like trienes and tetraenes all indicate probable integral membrane lipid peroxidation in seeds subjected to accelerated ageing. A reduction in the total content of food reserves like carbohydrate, reducing sugar and protein was found in aged seeds. A decreased activity of the enzymes acid phosphatase, phosphomonoesterase and dehydrogenase was noticed during accelerated ageing. A substantial increase in total free amino acids and in the activity of amylase and protease confirm the degradation of stored biomolecules in the seeds during ageing. The effect of these biochemical changes in relation to membrane deterioration and the breakdown of larger biomolecules is also discussed.