Phytochemical and Morphophysiological Responses of Dill (Anethum graveolens L.) to Foliar Application of Potassium Sulfate and Methanol Biostimulant

Background: The application of methanol biostimulant and potassium sulfate with reducing of photorespiration and transpiration in C3 plants, increasing the absorption of water and food, and biosynthesis of amino acids can have a direct or indirect effect on the growth and metabolic index of plants. Objective: This study was directed to investigate the effect of methanol and potassium sulfate foliar application on morpho-physiological and phytochemical changes in dill. Methods: This study was conducted as a factorial experiment based on randomized complete block design at institute of medicinal plants. Experimental treatments included foliar application of methanol at 3 levels (0, 20, 40 v/v%) and potassium sulfate at 4 levels (0, 1, 1.5, 2 g.L-1). Results: Methanol application increased the leaf and stem dry weight, and inflorescence fresh weight. Foliar application of different levels of potassium sulfate also increased the plant height, leaf dry weight, and inflorescence and shoot fresh weight. The use of methanol was not effective on the amount of essential oil in the dill. But, increased the amount of α-pienene. Low concentration of methanol increased the content of thymol, myrcene, α-phellandrene, and p-cymenen. So, increasing the concentration of methanol reduced their amount. Conclusion: Phytochemical and morphophysiological traits of dill were increased with application of methanol and potassium sulfate. As, the highest amount of leaf and stem dry weight, inflorescence fresh weight, and α-pienene was obtained with 40% methanol application. Also, the use of 2 g.L-1 of potassium sulfate produced the highest amount of plant height, leaf dry weight, inflorescence and shoot fresh weight