NITROGEN-METABOLISM OF YOUNG BARLEY PLANTS AS AFFECTED BY NACL-SALINITY AND POTASSIUM

In a solution culture experiment with 31 days old barley plants (var. Miura) the influence of NaCl-salinization (80 m M) and KCl addition (5 and 10 m M) on the uptake and turnover of labelled nitrogen (15NH415NO3) was studied. Labelled N was applied for 24 h at the end of a 20 days' salinization period. Salinization impaired growth and incorporation of labelled N into the protein fraction paralleled by accumulation of labelle dinorganic N. All salt effects were much more pronounced in the shoots than in the roots. Potassium addition enhanced N uptake (total15N-content) and incorporation into protien, reduced the accumulation of inorganic N and improved the growth of salinized plants. The presented data support the point of view that impairment of protein (enzyme) metabolism is an important aspect of salt stress which is probably induced by the disturbance of the K/Na balance of the tissues under saline conditions. © 1979 Martinus Nijhoff.