A comparison of different chemicals for osmotic treatment of vegetable seed

SUMMARY Samples of carrot, celery, leek and onion seed were treated before sowing by imbibition in osmotic solutions of polyethylene glycol 6000 (PEG), glycerol and potassium dihydrogen orthophosphate (KH2PO4). The solutions were sufficiently concentrated to prevent germination during treatment, and within each species, the amount of water taken up by the seeds during treatment did not vary greatly between solutions. All treatments increased the rates of seed germination and seedling emergence compared to untreated controls, but glycerol‐treated seeds germinated and emerged significantly more slowly than did PEG‐ and KH2PO4‐treated seeds. The effects of PEG and glycerol treatments on percentage germination and seedling emergence were small, but KH2PO4 treatment tended to reduce percentage germination and emergence, most markedly in leek and one cultivar of celery. It is concluded that PEG treatment gives the most consistently beneficial effects for the range of species tested.