Evaluation changing of essential oil of laurel (Laurus nobilis L.) under water deficit stress conditions

The effects of water deficit stress on growth and essential oil yield and composition of Laurel ecotypes (Annaba and Bardo) were studied. The factors studied included two stress intensities of permanent stress: 60% (S1) and 20% (S2) of field capacity or to cyclic water stress, plants being re-watered when the soil moisture dropped to 60% (S11) or 20% (S22) of field capacity. The results of this experiment showed that Relative Growth Rate (RGR), Leaf Mass Area (LMA) and chlorophyll content decreased under water stress especially under severe stress S2. For both ecotypes, essential oil yield was reduced under water deficit stress but essential oil% increased under this condition. Eight six components were determined in essential oils, which were mostly oxygenated monoterpenes. The main components were found to be 1,8-cineol in two ecotypes. In Annaba, 1,8 cineol increased with permanent stress (S1 and S2) and diminished by 50% under cyclic severe stress (S22) but in Bardo, we note that 1,8 cineol increased with water stress, this increase was much higher under cyclic stress (S11 and S22). Water stress decreased the constituents of alpha-terpinyl acetate, Sabinene and linalool for Annaba. For Bardo, alpha-terpinyl acetate increased under water stress. 2016 Elsevier B.V. All rights reserved.