Role of Osmolytes in Enhancement of Plant Abiotic Stress Tolerance

Plants are subjected to various external abiotic stress factors like heat, drought, cold, salinity and heavy metal pollutants in soil. These have a deleterious effect on their growth and yield parameters. It depends on the extent of exposure to a particular abiotic stress factor. However, plants have adapted to these environments gradually by way of some kind of tolerance or by an innate resistance caused by changes in its morphological, biochemical and physiological characteristics. One such biochemical change is the synthesis of osmolytes in plants to protect themselves from oxidative damage caused by stress. Osmolytes are also called osmoprotectants, cytoprotectants or compatible solutes. There are different classes of osmolytes produced by plants. This chapter deals with the biochemical and molecular basis for the production of osmolytes in plants, and their types, significance and role in the abiotic stress tolerance in plants.