Bedi, SeemaPaul, Amandeep2017-06-082017-06-082016http://krishikosh.egranth.ac.in/handle/1/5810018861Rapid loss in viability of onion seeds during seed storage is a major problem. In the present study, seeds of onion (Allium cepa L.) cv. Punjab Naroya harvested in the month of June were subjected to three post harvest storage procedures, viz; refrigerator storage at (5⁰C; 30% RH) for 4 months (considered as fresh seeds), room temperature storage for 4 months (stored seeds) and accelerated aged seeds. Refrigerator stored seeds were subjected to accelerated ageing at (50º C; 90% RH) for 3, 6, 9 and 12 days respectively. The refrigerated stored seeds showed maximum germination percentage (94%) while seeds accelerated aged for twelve days gave least germination percentage (62%). As the duration of ageing increased, there was a marked reduction in seedling length, fresh and dry weight. All the ageing treatments resulted in membrane damage, as is evident from higher solute leakage in aged seeds. Besides physiological changes, significant changes in biochemical parameters were also observed due to ageing. Increase in ageing duration decreased the activities of enzymes viz; peroxidase, catalase and α-amylase. There was a reduction in contents of total starch and total soluble proteins whereas, the total soluble sugars and total free amino acids increased with accelerated ageing. The amount of ascorbic acid, α-tocopherol and DNA also reduced with accelerated ageing.ennullThesis