[Objective] This study aimed to investigate the physiological and biochemi- cal effects of lanthanum （La3＋）, cerium （Ce3＋）, zinc （Zn2＋） on rice roots and explore the environmental effects of excessive application of rare earth. [Method] By using rare earth elements La3＋ and Ce3＋, and nutritional and toxic heavy metal element Zn2＋ as stress factors, the effects of these three elements on the germination of rice seeds, growth and development of seedlings were studied and compared by using tissue culture method. [Result] La3＋, Ce3＋ and Zn2＋ had no significant effect on germi- nation rate of rice seeds but significant inhibition effects on the growth of roots and shoots of rice seedlings, and the inhibition effects of rare earth elements in high concentrations were stronger than Zn2＋; the content of soluble protein in rice roots showed a rising-decreasing trend with the increasing concentrations of three metal ions, La3＋ and Ce3＋ were more sensitive than Zn2＋; the activities of CAT and POD increased with the increasing concentrations of La3. and Ce3＋, while the SOD activity had shown the tendency of decreased first and increased later; the three metal ions all could significantly stimulate the rapid accumulation of MDA in rice roots. La3＋ and Ce3＋ had stronger toxic effects at high concentrations than Zn2＋, [Conclusion] Toxic mechanism of rare earth elements La＋ and Ce3. is similar to that of heavy metal el- ement Zn2＋. Rare earth might become a new type of pollution in the long run.
