Effects of water deficit stress on Salvia leriifolia Benth. yield and essential oil composition

The effects of water deficit on yield، essential oil contents and composition of Noroozak (Salvia leriifolia Benth.) were investigated at Khorasan-e-Razavi Agricultural and Natural Resources Research Center، Mashhad-Iran. The treatments were deficit irrigation based on actual evapotranspiration (ETc) at the rate of 100% (fully irrigated)، 66. 6% (moderate stress)، 33. 3% (severe stress) and non-irrigated (control). The experiment was analyzed in a randomized complete block design with three replications. Results indicated that the essential oil percentage of green leaves and flowering stem in severe stress and control was significantly (P≤0. 05) higher than that of fully irrigated treatment. The highest and lowest dry matter yields were obtained in fully irrigated and control treatments، respectively. Severe deficit (P≤0. 05) decreased the essential oil yield significantly but it was not affected in moderate stress. Results also showed that 1، 8-cineol، β-pinene and borneol were the main essential oil constituents in all water deficit treatments، included nearly 50% of total essential oil contents. The above essential oil constituents in control treatment increased by 21. 1%، 7% and 15. 3% in green leaves and 39%، 12% and 55% in flowering stems in comparison with fully irrigated treatment. However cedren-13-ol and δ-cadinene decreased by 58. 5% and 46% in green leaves and 52% and 14% in flowering stems، respectively.