Evaluation of Spray Solution of Salicylic Acid and Water Stress on Medicinal Plant Verbascum songaricum

Since application of salicylic acid can increase tolerance to drought stress by improving metabolic pathways and increasing net photosynthesis, and in order to investigate the effect of application of salicylic acid and drought stress on some morphological and physiological traits of the Verbascum plant, the experiment was conducted in the form of chopped plots in the form of a complete block design. Randomization was done in four replications in the conditions of the research farm of Azad University, Isfahan Branch. The present study was conducted with the aim of determining the effect of salicylic acid application at three control levels, 50 and 150 ppm, and water deficit stress at two levels of regular irrigation and water deficit stress (irrigation at the time of 50% soil crop capacity). Finally, root length, dry weight, number of secondary branches, number of leaves, number of flowers on the main stem, height of flowering stem, carotenoid, chlorophyll b, chlorophyll a antioxidant and anthocyanin were evaluated. The test results showed that stress had a reducing effect on growth and effective factors on performance. As a result of stress, the ratio of leaf area first decreased, but increased with increasing dryness. The initial decrease of this characteristic was due to the decrease in the leaf area, and its final increase due to the more severe decrease in the dry weight of the entire aerial organ compared to the leaf. The application of salicylic acid improved the morphological and physiological characteristics of verbascum under the stress of low irrigation. While, the treatment of 50 ppm salicylic acid showed the greatest effect on most of the studied traits. As a result, the use of salicylic acid is recommended to improve the vegetative growth and increase the reproductive efficiency of the Verbascum plant and reduce production costs under stress conditions. In the present study, salicylic acid foliar application showed high efficiency in increasing the yield of the Verbascum plant in Isfahan weather conditions.