effect of water deficit stress on yield and essential oil components of rosa damascena herrm

To investigate water deficit stress on yield and essential oil components in rosa damascena herrm., an experiment was conducted in a completely randomized block design with three replications in karaj/ iran. the treatments included 90 mm (severe stress) and 45 mm (mild stress) of cumulative evaporation from the surface of the class a evaporation pan that was compared to the control treatment (no stress). combined analysis performed in the years. the studied properties included flower yield, essential oil percent, essential oil yield, and some essential oil components in the r. damascena. the essential oil of fresh flowers was extracted using the water distillation method by the clevenger apparatus. the essential oil components were identified using gc and gc/ms. the results showed that the effect of year and water deficit stress was significant on flower yield, essential oil yield, and some components in the essential oil. maximum flower yield was obtained in the second year without stress conditions (1208 g/plant), significantly different from the others. in the essential oil, citronellol, and geraniol increased due to water deficit stress and included 24.48 and 2.89%, respectively. applying water deficit stress reduced the amount of nonadecane, eicosane, and heneicosan. by applying different levels of water deficit stresses can be modified and manage the components in the essential oil of the r. damascena.