Impact of Foliar Spray of Ethephon, Water Stress, Organic and Inorganic Fertilizers on The Essential Oil Composition of Foeniculum vulgare Roots.

Objectives: Essential oils (EOs) are valuable natural products whose composition pattern, concentration of individual components and yield depend on many intrinsic and extrinsic factors. This study aimed to evaluate the impact of foliar spray of ethephon, water stress, organic and inorganic fertilizers on the EOs composition of Foeniculum vulgare, Miller, var. Dulce roots. Methods: Automated rapid headspace solid phase micro extraction (SPME) was applied for the extraction of volatile components combined with gas chromatography coupled to mass spectrometry GC/MS for identification of the volatile compounds. Results: forty two volatile components were identified in Foeniculum vulgare, Miller, var. Dulce roots which were dominated by hydrocarbons (55.36%-87.2%) with monoterpenes being the major class of components (53.15%-87.08%) in the six various applied conditions. Dehydro-p-cymene represented the major constituent (55.8%) in the oil of the non-treated control plant while limonene was the major component in both condition 4 and 6 upon applying drought stress, while alpha terpinolene is the major component in conditions 1, 2, 3 and 5 (30.59%, 39.93%, 50.37% and 35.41% respectively) using different organic and inorganic fertilizers. Conclusion: It is concluded that manipulation of agricultural techniques strongly affects biosynthesis and accumulation of essential oils obtained from Foeniculum vulgare Miller var. dulce roots.