ELECTROPHORETIC MODIFICATIONS OF THE SOLUBLE LEAF PROTEINS OF SUAEDA-MARITIMA VAR MACROCARPA, ATRIPLEX-HORTENSIS AND PHASEOLUS-VULGARIS IN RELATION TO THE SODIUM CONTENT OF THE CULTURE-MEDIUM

The study of the growth and metabolism of young plants grown in the presence of salt enables their classification according to their increasing sensitiveness to NaCl: S. maritima (L.) Dum. var macrocarpa Moq., A. hortensis L. and P. vulgaris L. The influence of salinity on the evolution of soluble leaf proteins was compared in the 3 plants grown on culturing solutions more or less rich in salt. Examination of electrophoregrams emphasizes the qualitative stability of the protein macromolecules. The protenome of the obligate halophyte S. maritima var. macrocarpa is characterized by its richness in high molecular weight proteins. With A. hortensis, a salt-resistant plant, accumulating Na+ in its aerial organs, the salt induces a progressive increase of the synthesis of a high molecular weight proteinaceous fraction. In contrast, P. vulgaris, a plant very sensitive to NaCl, does not transport Na+ into the tissues analyzed. In this species the salt does not induce a detectable change in the soluble proteins. The increased synthesis or the preservation of the high molecular weight proteins in the resistant or halophilic plants could reflect an adaptation mechanism to hypersaline conditions.