Interactive effects of sodium chloride and nitrogen on growth and ion accumulation of a halophyte

A sand culture experiment was conducted with a total of 20 treatments including 5 sodium chloride (NaCl) levels (0, 50, 100, 2,00, and 500 mM) and 4 nitrogen (N) levels (0, 3, 7.5, and 15 mM) to evaluate the interactive effects of NaCl and N on the growth and ion accumulation of the halophyte Suaeda salsa. Under 0 mM N condition, NaCl did not affect plant height significantly, while it increased branch number and root dry weight. Addition of N increased plant growth significantly; this increase was greatest at moderate level and further increase of N concentration did not increase growth significantly. Sodium chloride concentration 50 mM stimulated plant growth in moderate levels of N. Plant growth was significantly inhibited by 500 mM NaCl. Sodium uptake increased with increases of NaCl concentrations, while uptake of potassium (K), calcium (Ca), and magnesium (Mg) decreased. Addition of N increased Na uptake, and decreased K, Ca, and Mg uptake compared with no N treatment. Potassium/Na ratio in plants decreased with addition of 3 mM N, but was unaffected by further increasing N concentration. Ca/Mg ratio in plants increased by addition of moderate N and then decreased by further addition.