The effect of salinization of water on the growth rate and nickel accumulation capacity of Lemna gibba was studied under laboratory conditions. At high salinity (375 and 500 mol m(-3) NaCl), we observed that decreasing growth rate with increasing water salt level. Especially, at a salinity of 500 mol m(-3) NaCl, the net growth rate became negative. Additionally, growth rate of roots was significantly reduced at salinity of 250 mol m(-3) NaCl and significantly reduced at 500 mol m(-3) NaCl compared to a freshwater control. Biomass production was inhibited by an increase in salinity. Furthermore, high salinity caused decreasing nickel accumulation by L. gibba. In this study, a simple model was created according to data obtained from this study. The model has suggested that salinity is an important factor in limitation of growth of L. gibba.