Effect of Selenium and Silicon Foliar Spraying on Some Physiological Traits and Yield Parameters of Origanum vulgare L. under Drought Stress

Selenium (Se) and silicon (Si) are identified to affect plant physiological attributes and yield parameters. Se and Si’s effective roles in reducing various environmental stresses in plant of Origanum vulgare L. are unknown and need to be investigated. This study aimed to examine the role of Si and Se application on O. vulgare under drought stress and the effect of these two elements on physiological traits and yield parameters of O. vulgare. The impact of the foliar spraying of Se and Si under drought stress conditions was studied through a split factorial experiment with three replications in greenhouse conditions at the Yazd University. Drought, as the first factor in three stress levels of 30, 70 and 100% of field capacity, and nutrient factors including Se in three levels of control, 15 and 30 mg/l, and Si in three levels of control, 150 and 300 mg/l were sprayed. Foliar spraying of Se 30 mg/l had a significant effect on the increase in proline, soluble sugar, chlorophyll, carotenoids, phenolics compounds, and fresh and dry shoot weights. The foliar spraying of Si 150 mg/l had a significant effect on the increase in proline compared to the control traits. The change in foliar spray quantity of Si has no significant impact on changes in yield parameters. The combined foliar spraying of Se and Si to reduce the effects of drought stress has been more effective than applying just one of these elements in improving the physiological attributes of O. vulgare. The solution of 30 mg/l Se and 15 mg/l Si has a higher yield under drought stress conditions of 70% of the field capacity.