Abstract
Onion (Allium cepa L.) is a biennial crop of high commercial value in Pakistan. Onion is considered as salt sensitive plant species. The present investigation was carried out to investigate the effect of salinity on onion and its alleviation through exogenously applied gibberellic acid (GA(3); 100 mg L-1). Foliar application of GA(3) (100 mg L-1) was applied on onion seedlings grown under three levels (0, 2 or 4 dS m(-1)) of salinity after 45 days of sowing. Results revealed that growth parameters and total soluble protein (TSP) contents declined with increase in soil salinity level. While, antioxidant enzyme activities (CAT, SOD and POD) were increased with salinity. However, exogenously applied GA(3) significantly enhanced the plant growth and TSP in onion seedlings. Interestingly, CAT, SOD and POD concentration decreased with GA(3) application which depicts stress alleviation in saline stressed onion plants due to GA(3). It was concluded that the growth of onion could be enhanced to some extent by the application of GA(3) under salinity stress.