Growth, Physiological and Biochemical Traits of Sage under the Exogenous Stimulating and Stress Factors

Sage ( Salvia officinalis L.) belonging to the Lamiaceae family, as the main herb in the world is cultivated in many countries for extraction of essential oil from the leaves. One of the most important uses of the plant is to use its leaves as raw material in pharmaceutical and cosmetics industries. Interaction effects of exogenous jasmonic acid (JA) at different concentrations (0.00, 400, and 600 µM) and the applied of arbuscular mycorrhizal fungi (AMF) in soil under different moisture conditions (control or non-stress, slightdrought, and mild drought stress) on growth, and morphophysiological characteristics of sage and the quantity and quality yield of essential oil from the sage leaves were investigated. The constituents in the essential oils from the sage leaves were analyzed by GC-FID and GC/MS. Results indicated that the inoculation with AMF meaningfully increased the growth parameters sage, while, the foliar spray of JA improved only physiological traits such as soluble sugar, proline, and anthocyanin in the leaves. Experimental treatments individually increased the concentrations of 1,8-cineole in the essential oils. The interaction effects including AMF × JA, AMF × irrigation, and JA × irrigation significantly affected the essential oil yield and the morphological characteristic of sage. The highest value of the essential oil yield was obtained from AMF-inoculation × mild drought × JA at 400 µM. Finally, the exogenous application of JA along inoculation with AMF changed some characteristics of the sage plant under drought stress condition. Indeed, AMF-inoculation and the foliar spraying of JA had synergistic effects on the amounts secondary metabolites of sage especially, 1,8-cineole. In conclusion, we found that the exogenous JA along the inoculation of arbuscular mycorrhizal improves growth characteristics and quality of the essential oil of sage and enhances water deficit tolerance.