Effectof waterdeficit stress on secondary metabolites profileof some Iranian medicinal plants from Lamiaceae family

Environmental stresses such as high and low temperature, salinity, water deficit, toxic metal ion concentration, UV radiation and pathogen infection are potentially harmful to the plants. In arid and semi-arid regions of the world, such as Iran, water stress is one of the most serious problems that can affect crop productivity and secondary metabolism. It can limit theplant growth and productivity through different mechanisms. Water deficiency not only reduces plant water content but also decrease cell turgor and plant growth, while it also generates harmful reactive oxygen species (ROS) such as superoxide radicals, single oxygen, hydroxyl radicals, and hydrogen peroxide. Due to limited rainfall in the Middle Eastern countries, such as Iran, the water availability is becoming the major challenge in production of herbs and other crops. As native medicinal plants are valuable crops in Iran and neighboring countries, understanding the dynamics of water stress on the chemical composition and productivity of their essential oil is very important. This article evaluated the effect of prolonged water stress on plant growth, essential oil content and constituents of some herbal medicines whicharerich source of essential oil (i.e., high yields) and phenolic monoterpenes.