This greenhouse research was conducted in the fall of 2012 in a controlled greenhouse Karaj, Iran, to evaluate the effect of various concentrations of salicylic acid foliar spray on different traits of two coriandrum sativum varieties under drought stress. Salicylic acid was applied in two stages and four concentrations (0, 4000, 8000 and 12000μM.l). Two varieties (Tehran & Hamedan) and irrigation levels (daily and once every three days) were studied. The experiment was conducted in the factorial form with 3 factors in the randomized complete design with 16 treatments and 3 replications. Each experimental unit was a planting tray with 72 places. Cultivation was done in special trays and planting trays irrigation were done equally until plants germination. Water stress treatment was applied one week after germination. Different levels of salicylic acid foliar were applied 10 days after stress beginning. There were no significant difference between all traits in two coriandrum sativum varieties. Although the concentrations of salicylic acid did not make significant effect on plant height, plant fresh weight, dry matter percent and lateral branches number, but concentration of 12000μM.l showed significant increase in the plant dry weight compared to the control and other concentrations with 58.79mg. Concentrations of 8000μM.l and especially 12000μM.l caused significant increase in chlorophyll index and decrease in plant proline. The highest essential oil percent observed in concentration of 4000μM.l with 0.147%. In short, salicylic acid improved the traits and reduced the negative effect of drought stress.
