Production and chemical composition of Mentha x piperita var. citrata (Ehrh.) Briq. essential oil regarding to different potassium concentrations in the hydroponic solution
This work aimed to evaluate the production of fresh and dry mass of leaves, stems and aerial parts, and the content and quality of lemon mint (Mentha x piperita var. citrata) essential oil as a result of four potassium (K) concentrations (276, 414, 552 and 690 mg.L-1) under hydroponic solutions. The experiment was carried out in the hydroponic NFT (Nutrient Film Technique) system. Leaves were separated and weighted to determine the fresh mass and part of them was used to extract oil in a Clevenger apparatus. The analysis of the oil chemical composition was performed in a gas chromatograph fitted with a mass spectrometer. The estimated concentration for the maximum fresh mass production of the leaves corresponded to 384 mg.L-1 K. The greatest K concentration proportionated an increase in essential oil content and yield per plant, but decreased linalool and linalyl acetate in the oil. Under the conditions the experiment was carried out, in order to obtain an adequate quantity of leaves for a higher essential oil yield per plant and linalool and linalyl acetate accumulus, the K concentration of 414 mg.L-1 is recommended in the hydroponic solution for the cultivation of lemon mint.