The effects of foliar application of some important micronutrient elements on essential oil content and components of Dracocephalum kotschyi Boiss.

Purpose: Dracocephalum kotschyi Boiss. belongs to the Lamiaceae family, is one of the important and endangered endemic species in Iran. The present study was conducted to investigate the effects of micronutrient elements application on the content and composition of essential oil of D. kotschyi Boiss. shoots in southwestern Iran (Shahrekord) in 2022 and 2023. Research Methods: Four foliar fertilizers including Fe, Cu, Zn and Mn were applied in 0, 20, 40 and 60 mg.l-1 in RCBD design by factorial layout and 3 replications. Findings: Results obtained from gas chromatography/mass spectrometry (GC-MS) showed 14 essential oil components. According to obtained results, applied micronutrients significantly influenced the essential oil content/ composition of D.kotschyi. In both years, the highest content of essential oil (0.98-0.99 %) was obtained in plants treated with 40 mg.l-1of micronutrients (Fe2Cu2Zn2Mn2) and the lowest content (0.59-0.66%) made by control plants (0 mg.l-1), however the plants treated by 60 mg.l-1of micronutrients in most characters were in a same group with the control plants. The most important chemical compounds that determine the quality of D. kotschyi essential oil including Neral (9.02-16.31%), Limonene (25.4-35.6%), Geranial (8.6-16.5%), Eucalyptol (3.89-8.01%) and Myrtenol (22.5-32.1%) were identified alcoholic monoterpenes. Limonene belonging to monoterpene hydrocarbons was the predominant constituent of the D. kotschyi. Limitations: There were no limitations to the report. Originality/Value: The foliar application of micronutrients at 40 mg.l-1 (Fe, Cu, Zn and Mn) can be a good strategy to improve the essential oil quantity and quality of D.kotschyi in cold and semi-arid climates.