| The biological effects of cesium（Cs+） in coexisting system of cesium and cadmium（Cd2+/Cs+） were studied by analysing characteristics of seed germination in chicory（Cichorium intybus L.）, contents of protein and proline, and metabolic changes of reactive oxygen species（ROS） with Cs+ single factor treatments[ρ（CsCl）20~140 mg·L-1] and Cd2+/Cs+ combined treatments[ρ（CdCl2+CsCl） 20 mg·L-1+20~140 mg·L-1] in seedlings. The results showed that：（1）As the increase of different Cs+ single factor processing concentration, there were no significant difference in germination potential（GP）, germination rate（GR） and germination index（GI）; there were the trends in which the soluble protein contents were generally declined, the contents of proline, H2O2 and MDA, O-2· productive rate, the activities of SOD and CAT were increased in general, and POD activities were improved.（2）In coexisting system of cesium and cadmium（Cd2+/Cs+）, SOD activities and O-2· productive rate were raised at first and then decreased as the Cs+ concentration improved, but there were the same trend as Cs+ single factor treatments about proline contents, CAT activities and others.（3）In comparison with the Cs+ single factor treatments, the soluble protein contents and SOD activities were lower, others were higher generally. It was concluded that there were no significant effects on the growth and ROS metabolism in chicory seedling under lower Cs+ single factor concentration[ρ（CsCl）20 mg·L-1], but the severe peroxide injure were produced by treatments with higher Cs+ single factor concentration[ρ（CsCl）60~140 mg·L-1] and Cd2+/Cs+ combined. There were possible alleviation of Cd toxicity under lower Cs+ concentration of Cd2+/Cs+ combined[ρ（CdCl2）20 mg·L-1+ρ（CsCl）20 mg·L-1], but there were obvious harmful synergistic effects under higher Cs+ concentration of that[ρ（CdCl2+CsCl）20 mg·L-1+60~140 mg·L-1]. |
