GROWTH, ION ACCUMULATION, AND NITROGEN FRACTIONING IN ATRIPLEX-BARCLAYANA GROWN AT VARIOUS SALINITIES

Effects of varying NaCl levels (50-400 mol/m3) on growth, ion accumula tion, 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 concent rations not exceeding 200 mol/m3, but fell to less than half when salt concentration was increased to 400 mol/m3. Potassium and calcium conc entrations in shoots were unaffected by root media salinities up to a concentration of 200 mol/m3 but declined at 400 mol/m3. Sodium and chl oride concentrations in shoots demonstrated an increase with rising sa linity, 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 slight ly when culture salinity was raised from 50 to 100 mol/m3 NaCl and the n remained constant up to an NaCl level of 400 mol/m3. Our results ind icate that A. barclayana is a highly salt-tolerant plant with leaves r ich in nitrogen, but high salt concentrations in the leaves and stems even at low salinities markedly reduce its potential as a fodder plant .