Establishing the large scale osmotic priming of onion seeds by using enriched air

Abstract

SummaryOnion seeds were primed in polyethylene glycol solutions (PEG) (‐1.5 MPa) for 14 days at 15°C on filter paper and in bubble columns containing 50 g seed litre‐1 PEG using air or enriched air (75% O2/25% N2) to aerate and suspend the seeds. Compared with untreated seeds, priming seeds in bubble columns using enriched air increased the percentage seed germination but it did not when air was used, or when seeds were primed on filter paper. Mean germination times (tm) were significantly reduced in all cases but the reduction was greatest using enriched air and least using air. The spread of germination times was significantly reduced only for seeds primed in enriched air.Drying seeds following priming reduced the percentage germination compared with untreated seeds, but only significantly for those primed in bubble columns using air. Drying also increased the mean germination times by 1.5 to 1.8 days (relative to primed seed which had not been dried). Seeds primed in enriched air were least affected. This increased time is that typically required for water re‐imbibition after drying.Priming with enriched air followed by drying gave the same number of normal seedlings as untreated seeds.