ABSTRACT
Environmental stress is defined as a set of physical and chemical factors of the environment that are unfavorable to the growth of a plant species, such as high or low temperatures, water deficit, ultraviolet radiation, and pollutant gases. The study of plant environmental stress is important, because (i) agricultural productivity worldwide has been greatly restricted by environmental stresses, and (ii) a high capacity to tolerate environmental stresses is the prerequisite to the immotile life of plants, which is affected greatly by ever-fluctuating environments.
