effect of drought stress and salicylic acid on yield and mucilage content of the medicinal herb plantago ovata forssk

since there is limited information on the simultaneous effect of drought stress and salicylic acid on yield and mucilagecontent of the medicinal herb, plantago ovata forssk is available, a pot experiment was conducted in factorial form basedon a randomized complete block design with three replications in jiroft, kerman province, south of iran. as the firstfactor, drought stress included four levels of irrigation: 100℅ field capacity (fc) (no stress), 75℅ fc (low stress), 50℅fc (medium stress) and 25℅ fc (high stress). in the second factor, salicylic acid had four levels: 0, 0.01, 0.5 and 1 mm. the results showed that maximum yield and yield components of p. ovata forssk were obtained with 100℅ fc andsimultaneous application of 1 mm salicylic acid. minimum amounts of yield and yield components resulted fromirrigation based on 25℅ fc with no application of salicylic acid. such an outcome revealed the significant role of salicylicacid in increasing the tolerance of plantago ovata forssk to drought stress.