Evaluation of Different Levels of Zeolite and Salicylic Acid on Some Growth Indices of Medicinal Plant (Thymus Daenensis) Under Drought Stress Conditions

This experiment was conducted as a split-plot factorial based on a randomized complete block design with three replications in the medicinal plants' farm of Islamic Azad University in 2017. In this experiment, water stress was considered as the main factor in four levels of irrigation including 100%, 75%, 50% and 25% of the plant water requirement in the main plots. In addition, the application of different levels of zeolite (including no application of zeolite, two, four, six tons per hectare), as well as application of salicylic acid at two levels (0.5 and 1 mM) were considered as secondary factors in the form of factorial on subsidiary plots. The results showed that the effect of different levels of water stress on the traits such as plant height, number of lateral branches, plant wet weight, leaf area index, number of flowers in inflorescence was significant at 1% and on plant dry weight was significant at 5%. Salicylic acid application was also significant on some traits such as flower number in inflorescence, leaf area and dry weight at the probability level of 1%, and on plant volume and wet weight at 5% level. In addition, the effect of different levels of zeolite application was significant on plant height, number of lateral branches, wet weight, dry weight, leaf area index, number of flower in inflorescence at 1% level.