The Influence of Ce on Spirodela polyrrhiza

In recent years, Rare Earth (RE) has been mined, smelted and applied largely. Because the Rare Earth element(REE) migrate from lithosphere to hydrosphere and biosphere, it may has a negative influence analogous heavy metal on aquatic environment. In this paper, the cerium ion´s influence on Spirodela Polyrrhiza was researched from concentration and valence state aspects quantificationally. The results showed that the different valence states of Ce had little impact on Spirodela Polyrrhiza. Under the condition of low Ce concentration (0.00-1.00mg/L), the growth of Spirodela Polyrrhiza was promoted, and the high cerium concentration( £¾ 1.00mg/L) can restrain the growth of Spirodela Polyrrhiza, the optimum accelerate concentration of Ce was near 0.65mg/L.