ABSTRACT
A variety of protective mechanisms have evolved in plants to allow them to acclimatize to unfavorable environmental conditions for survival and growth. It has been reported that amino acids, such as proline, alanine, valine, isoleucine, glutamic acid, arginine, serine, glycine, aspartic acid, amides such as glutamine and asparagine, and non-protein amino acids such as ɣ-aminobutyric acid, pipecolic acid, citrulline, and ornithine are accumulated in higher plants under different abiotic stress conditions [1], and thus may play a role in stress tolerance. The cellular source of these amino acids is the primary metabolic pathways [2]. Their main role is to increase the ability of cells to retain water without affecting the normal metabolism.
