Physiological and biochemical significance of antifreeze substances in plants

Plants produce several compounds to protect cells against fatal intracellular ice formation. Many overwintering plants accumulate sugars, amino acids, and other solutes that induce supercooling in the plants tissues on the molar depression of the freezing point. Recently, several antifreeze proteins and antifreeze compounds have been isolated from plants. The frost inhibition mechanisms of those antifreeze proteins and antifreeze compounds have been found to be different The former acts to inhibit ice crystal growth, while the latter acts to inhibit the nucleation of ice crystals. In this review, we will describe the physiological and biochemical roles of these compounds in the development of freezing tolerance in plants.