A factorial experiment base on randomized complete block design with three replications carried out to investigate the effect of salicylic acid at enhancing stress tolerance in petunia plants during 1392. Factors were two petunia varieties (Sonja pink and an Iranian variety), two irrigation levels (70 and 40 percent of FC) and three salicylic acid doses (0, 1 and 2 mM). There were significant differences between varieties in response to different irrigation levels and salicylic acid doses. Flower number per plant, flower diameter, leaf area, shoot and root dry weight, biomass, chlorophyll content, stomatal conductance decreased by higher drought level. Electrolyte leakage enhanced by drought stress. Destructive effects of drought stress on petunia, reduced by applying salicylic acid reduced. Morphological and ornamental characteristics of flowers improved by higher doses of salicylic acid. Electrolyte leakage decreased using 2 mM of salicylic acid. Results showed that drought tolerance decreased by salicylic acid in both varieties. Best results gained by applying 2 mM of salicylic acid.

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