Effect of Different Storage Conditions on Physiological and Biochemical Changes in Onion (Allium cepa L.) cv. Punjab Naroya Seeds

Rapid 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 conditions, viz; refrigerator storage at (5p C; 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 (50p 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, reduction in activities of peroxidase, catalase and-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, a-tocopherol and DNA also reduced with accelerated ageing.