Abstract

Lech G. Polanski, Andrew Khanifar and Witold Tadeusz

Peppermint (Mentha piperita L.) is one of the most important plants producing essential oil. Two experiments were conducted to determine the effect of drought stress on growth parameters, essential oil constituents and yield of peppermint. 5 levels of water deficit stress including D1 (100% field capacity-control), D2 (85% field capacity), D3 (70% field capacity), D4 (60% field capacity) and D5 (45% field capacity) were investigated during 4 months. Results indicated that drought stress motivated a significant reduction in all of the growth parameters and essential oil yield and percent. The highest values of growth parameters and essential oil percent and yield were observed under 100% field capacity (control). Also, the highest values of Mentone and menthofuran were obtained under 100% field capacity (control) and the highest values of menthol were obtained under 70% field capacity by using gas chromatography-mass spectroscopy (GC-MS).