Abstract. The temperature-dependent primary dormancy of cv Florida 683 celery seeds in darkness was broken by GA,, (2 X lo-' M) alone but other growth regulators such as BA, ethephon or daminozide were necessary to break dormancy of cv Lathom Blanching seeds in the presence of GA,, at this concentration. Although AgNO, partially inhibited both the ethephon-and BA-induced germination of cv Lathom Blanching seeds in the presence of GA.,,, in the dark it did not affect the promotive action of daminozidc. Ethephon did not overcome the inhibitory action of high concentrations of AgNO, in thelight. The ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG) did not inhibit the germination of cv Lathom Blanching seeds induced by growth regulators in the dark or in the absence of growth regulators in the light. Fusicoccin (FC) did not break celery seed dormancy unless applied in the presence of GA,, , . Germination of cv Lathom Blanching celery seeds treated with GA,,, at 16 "C in the dark was inhibited by the K+ ionophore benzo-18-crown-C-6 (18-C-6) and In the presence of Cal+ by the Ca*+ ionophore A23 187; the 18-C-6 inhibition was reversed by BA.It is concluded that the involvement of gibberellin in celery seed dormancy is not dependent on endogenous ethylene and is directly or indirectly controlled through the action of other hormones on transmembranc ion fluxes.