Effect of drought stress and foliar application of salicylic acid on some morphological ‎and physiologicalcharacters of withania (Withania coagulans Dunal.)‎

Withania is one of the most important medicinal species from economical point of view and its application in pharmaceutical industries and stabilization of sand in desert areas. This study was conducted to evaluate the effect of drought stress and foliar application of salicylic acid on some physiological and morphological characters of Withania at Khorasan Razavi Agricultural and Natural Resources Research and Education Center under green house conditions. A two factorial experiment was laid out in completely randomized design with three replications. The first factor, four levels of foliar application of salicylic acid (control, 1, 1.5, 2 mM) and the second factor, four drought levels (100, 80, 60 and 40 percent of field capacity). The results showed that drought stress and salicylic acid had significant effects (P≤1 percent) on physiological (proline content, ion leakage percent, SPAD, chlorophyll fluorescence) and morphological (shoot height and leave sourface) traits. Mean comparisons showed that the highest value of proline (3.99 µmol g-1 FW) was obtained in 1.5 mM salicylic acid and drought stress 60 percent field capacity. The highest value of ion leakage percent was obtained in the control treatment of salicylic acid and drought stress 40 percent of field capacity. According our results, revealed that the withania was tolerance drought stress and can be tolerance to 60 percent of field capacity. at all levels of drought stress. Since withania plant is valuable, salicylic acid can be increase the tolerance of this plant to drought.