ABSTRACT
Stress can be defined as any environmental factor that adversely affects plant growth, development, and the final yield in crops. Plants can respond to stress stimulus in several ways, including an escape response, i.e., survival of stress treatments (stress periods) in a metabolically inactive stage such as seeds, or an active stress response, underlying either stress avoidance or stress tolerance. Stress avoidance means activation of plant biological mechanisms leading to maintenance of unstressed (control) conditions at plant cell level, while stress tolerance means an active plant acclimation to altered conditions at the cellular level (e.g., decreased cell water content, increased salt ion levels) inducing an enhanced stress resistance to an altered environment (Levitt, 1980).208
