The Effects of Imbibition Drying Treatments on Wheat Seeds

SUMMARY Wheat seeds were imbibed and re‐dried under conditions that did not give rise to radicle protrusion through the seed coat. When seeds pre‐treated in this way were planted in moist vermiculite, coleoptile emergence was faster than from untreated seeds. This advancing effect on coleoptile emergence (‘seed invigoration’) was most marked when the seedlings were grown at low temperature or under osmotic stress (i.e. under unfavourable conditions). The seed‐borne pathogen Septoria nodorum was not affected by an imbibing‐drying treatment. Conditions of imbibition and drying giving optimal invigoration are described and data on the metabolism of untreated and invigorated seeds are presented. Oxygen uptake and [14C]‐leucine incorporation into protein were more enhanced in aleurone layers than in embryos isolated from invigorated seeds. Both untreated and invigorated seeds showed very low α‐amylase levels when dry, although a‐amylase activity developed more rapidly in invigorated seeds during germination. Gibberellic acid alone was not able to replace an imbibing‐drying treatment.