Enhancement of Welsh Onion (Allium fistulosum L.) Seed Vigor by KNO3 Priming

Welsh onion (Allium fistulosum L.) is one of the important vegetable crops in China. However, the seeds of this crop are short-lived and their vitality tends to be easily lost in the course of storage. The present study was conducted to elucidate the effects of welsh onion seed priming with potassium nitrate (KNO3) on seed vigor and on other such related mechanisms during twelve months of storage. The priming treatment improved the germination rate and vigor index of welsh onion. Membrane deterioration of welsh onion seeds was significantly alleviated by the priming treatments, as assayed by using soluble sugar content and electrical conductivity of the seed leachates. The accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in primed seeds was reduced compared with non-primed seeds. The increased activities of antioxidant enzymes, such as dehydrogenase, superoxide dismutase (SOD), and catalase (CAT) in primed seeds correlated with seed vigor and lipid peroxidation. This study provided the theoretical basis for improving the initial quality of welsh onion seeds using KNO3 priming.