Abstract
Onion (Allium cepa L.) seeds were primed for 4–6 days at 15°C on a filter paper moistened with trehalose or raffinose solutions. These priming treatments accelerated the speed and uniformity of germination, and were comparable to the polyethylene glycol (PEG) treatment, which is used widely as a priming technique. Onion seeds stored at 5, 15 and 22°C for 9 weeks after priming with trehalose or raffinose still showed high germination speed and uniformity. The priming effect of trehalose was observed in all three onion cultivars tested even though there were differences in the effect based on their original germination abilities. Under stressful conditions such as NaCl (100 mM), PEG (10%) or low temperature (15°C), primed seeds treated by trehalose (0.4 M) or raffinose (0.4 M) showed germination rates as high as 30–50% after 2 days incubation. This is in contrast with germination rates of around 2% in the unprimed seeds. From these results, the trehalose and raffinose treatments are considered useful to improve seed germination ability in onion seeds.
