La3+对Cd2+胁迫萝卜幼苗的防护效应

目的]为重金属污染植物的生态防御提供参考。方法]用不同浓度CdCl2（0、1×10^-4、5×10^-4、1×10^-3、5×10^-3mol／L）处理萝卜幼苗，各处理整株喷洒等量工丑（N0，），溶液（以喷洒等量蒸馏水为对照），研究镧对铬胁迫下萝卜幼苗的防护效应。结果]镉胁迫下，萝卜幼苗的株高、主根长、根系活力、叶绿素含量和硝酸还原酶活性均有所下降，质膜透性、脯氨酸含量、过氧化氢酶（CAT）及过氧化物酶（POD）活性均显著升高；喷洒一定剂量（15mg／L）La（NO3），后，萝卜幼苗的根系活力、叶绿素含量、硝酸还原酶活性均有所升高，质膜透性、脯氨酸含量均有所降低。结论]适当剂量的稀土元素镧可减轻重金属元素铬对萝卜幼苗的伤害。

Protective Effect of La~(3+) on Radish Seedlings under Cd~(2+) Stress

Objective ] The study was to provide the reference for ecological defense of plants polluted by heavy metals. Method ] The radish seedlings were treated by CdCl, with different concn. (0,1 ×10~(-4) ,5× 10~(-4) ,1 ×10~(-3),5× 10~(-3) mol/L) ,and the whole plant in each treatment was treated by foliage spray of La( NO_3)_3 with the same amount( with the treatment spraying the same amount of distilled water as CK) ,the protective effect of La~(3+) on radish seedlings under Cd~(2+) stress was studied. Result ] Under Cd~(2+) stress, the plant height, main root length, root activity,chlorophyll content and nitrate reductase activity of radish seedlings were all decreased somewhat,and their membrane permeability, proline content and activities of catalase ( CAT) and peroxidase ( POD) were all increased somewhat. After spraying of La( NO_3)_3 with a certain dose (IS mg/L) .the root activity,chlorophyll content and nitrate reductase activity of radish seedlings were all increased somewhat,and their membrane permeability, proline content were all decreased somewhat. Conclusion ] Rare earth element La with proper dose could reduce the damage of heavy metal Cd on radish seedlings.