مشخصات پژوهش

Peppermint (Mentha × piperita L.) and Japanese mint (Mentha arvensis L.), as the prominent menthol bearing species are widely cultivated and have a considerable share in the global essential oil trade. In this research, the effects of two different planting dates (spring and autumn), diverse cutting time, and alluvial soil conditions were investigated on the growth and essential oil compounds of M. × piperita L. var. Black Mitcham and M. arvensis var. piperascens Holmes in Çukurova Region/Turkey, during 2011􀀀 2014. According to the results, despite the relative superiority of M. arvensis; no significant difference was recorded in the growth potential of two species. However, the content and yield of M. arvensis essential oil (4.8 % and 94 L ha􀀀 1) were substantially higher than M. × piperita (2.8 % and 43 L ha􀀀 1). In terms of plant height, dry biomass, leaf dry weight, and essential oil yield, the spring planting date was significantly superior to autumn. Among the six cuttings, the data of the first cuttings were significantly higher than the second cuttings for each year. The major essential oil constituents of M. × piperita were menthol (22.5–44.6 %) and menthone (13.8–37.4 %). Overall, menthol was more abundant in the spring cultivation of M. × piperita. In contrast, menthone amounts were higher in autumn cultivation. Menthol (53.6–70.5 %) was the major compound of M. arvensis. Isomenthone (4.5–17.7 %), menthone (3.3–14.5 %), and α- pinene (3.6–11.1 %) were the other major oil components of M. arvensis. Menthol content significantly decreased from the fourth cuttings. Although a declining trend in the yield of species was observed over time, the results were acceptable considering the restrictive conditions of the alluvial soils. All in all, without imposing the limits on the cultivation areas of the strategic agricultural crops; the cultivation of medicinal plants would be advisable with the plenty of alluvial lands.