Growth, ion accumulation, and nitrogen fractioning in Atriplex barclayana grown at various salinities.

Abstract

Effects of varying NaCl levels (50-400 mol/m3) on growth, ion accumulation, and nitrogen fractioning in Atriplex barclayana were studied in a greenhouse experiment using a water culture method. Relative growth rate of shoots was maintained at a high constant level at NaCl concentrations not exceeding 200 mol/m3, but fell to less than half when salt concentration was increased to 400 mol/m3. Potassium and calcium concentrations in shoots were unaffected by root media salinities up to a concentration of 200 mol/m3 but declined at 400 mol/m3. Sodium and chloride concentrations in shoots demonstrated an increase with rising salinity, particularly when NaCl level was increased from 50 to 100 mol/m3. Total nitrogen concentration in leaves was relatively high (3.51-3.72% of dw) at salinities between 50 to 200 mol/m3 NaCl but decreased significantly at 400 mol/m3 NaCl. Glycinebetaine in leaves rose slightly when culture salinity was raised from 50 to 100 mol/m3 NaCl and then remained constant up to an NaCl level of 400 mol/m3. Our results indicate that A. barclayana is a highly salt-tolerant plant with leaves rich in nitrogen, but high salt concentrations in the leaves and stems even at low salinities markedly reduce its potential as a fodder plant.