Tolerance mechanisms of medicinal plants to abiotic stresses

There is no doubt that rapid or gradual environmental changes are the direct threat to agricultural sustainability and food security. Plants have developed different mechanisms to respond to environmental stresses. Short-term changes in environmental factors can lead to cumulative reactions, while gradual changes can lead to adaptation in plants. Individual’s response to environmental stressors depends on many factors such as type and duration of stress and plant species. The exposure of plants to adverse environmental conditions such as extremely high or low temperature, light stress and ultraviolet (UV), heavy metals, water shortage, air pollutants, nutrients deficiency, and salt stress results in the generation of reactive oxygen species including superoxide, hydrogen peroxide, and hydroxyl radical. Plants have developed a set of different mechanisms for adaptation and survival under severe environmental conditions. The adaptation and/or survival of plants grown under harsh environments cause(s) remarkable variations at the cellular and molecular levels. Among the most critical environmental factors, both temperature and water significantly affect plants geographical distribution and consequently agricultural sustainability in different regions of the world.