Biochemical Investigations on Vigour Enhancement in Fresh and Aged Seeds Upon Seed Priming in Cowpea [Vigna unguiculata (L.) Walp.]

Background: Loss in seed quality that occurs from maturity in the field to storage, leads to seed deterioration. Storage of cowpea seeds under ambient, hot and humid conditions is very problematic since these conditions deteriorate seed quality faster. Seed deterioration is associated with many metabolic defects that occur due to changes in enzyme and protein levels. Method: The present study was performed to verify the effects of cowpea [Vigna unguiculata (L.) Walp.] seed priming (GA(3), ammonium molybdate, Ca Cl-2, KBr, Mg (NO3)(2), ZnSO4, Hydro priming and dry non primed) with fresh and accelerated aged seeds. Result: The deterioration was rectified to the extent possible by the technique of seed priming. SDS PAGE profiling indicated the differential expression of proteins with seed priming. Esterase and peroxidase enzyme which were completely lost as a result of ageing showed reappearance after priming. The band intensity as well as the number of proteins induced by seed priming increased over control. Priming also restored the lost seed vigour in aged seeds due to reactivation of proteins in old seeds and expression of these proteins in priming treatments are related to priming induced proteins in contrast to their absence in the aged seeds which are necessary for germination and longevity of seeds. The present study concluded that priming with GA(3) (100 ppm) and Ammonium Molybdate (10(-3) M) for 24 hours in aged seeds of cowpea showed increase enzyme activity, restored almost entire protein profile and esterase and peroxidise isozyme profile as it allowed repair system to combat sub-cellular damage and activated synthesis of enzymes and proteins.