Growth promotion by sodium in amaranthaceous plants

ABSTRACTThe amaranthaceous dwarf glasswort, Swiss chard, table beet, spinach and Mexican tea were grown in solutions containing 0, 20, 40, 80, 120, 160, 180 and 200 mol m−3 sodium chloride (NaCl). Maximum growth and increase of biomass production compared to that at 0 mol m−3 of dwarf glasswort was observed at 200 mol m−3 (245%), and Swiss chard (146%), table beet (128%) and spinach (138%) at 80 mol m−3. The growth of these species increased with increasing sodium (Na) concentration of shoot until it reached 4.18, 2.42, 1.60 and 1.58 mol kg−1, respectively. These indicate that the order of Na-loving character is dwarf glasswort >> Swiss chard > table beet = spinach. The water contents increased with increasing Na concentration until growth reached maximum in dwarf glasswort and Swiss chard. In these highly Na-loving species, Na is activity transported to shoots and utilized for producing osmotic pressure to absorb water.