Changes in Chloroplast Membrane Lipids during Adaptation of Barley to Extreme Salinity.

During adaptation of barley (Hordeum vulgare L.) seedlings to extremely high concentrations of sodium chloride in the root space, the content of galactolipids of chloroplast membranes decreased considerably. Alterations in membrane lipids were due to the high concentration of ions rather than to the increase in the water potential. Sodium chloride was accumulated in the leaf cells and affected lipid-synthesizing enzymes such as galactosyl transferase and acylase which are attached to the chloroplast envelope. The return of salt-adapted barley seedlings to a nutrient solution with low salt concentration resulted in a reversal of the observed changes. It is suggested that the decrease in content of galactolipids in biomembranes is one of the factors causing increased salt resistance in barley plants which are adapted to extreme salinity.