... leucine, and valine, the nonprotein amino acids citrulline and orni-thine (Orn)), together with the imino acid Pro, and the amides such as glutamine and asparagine are accumulated in higher plants ... of the membrane poten-tial and thus to a destruction of biomembranes (Schulze et al. 2002 ) . On the other hand, the hydration and charge of proteins are negatively infl uenced, so that their ... Furthermore, more energy can be provided for energy-dependent tolerance mechanisms such as the synthesis of compatible solutes and antioxi-dants. Therefore, the salt and drought tolerance and...