中文摘要：

[目的]研究白菜对镧（La）、锌（Zn）胁迫的生理生化应答。[方法]以稀土元素La和兼具营养与毒性的重金属元素Zn为胁迫因子,采用组织培养法比较研究两者对白菜种子萌发及幼苗生长发育的影响。[结果]La、Zn对白菜种子萌发率影响很小,但在较高浓度下对幼苗根、茎及鲜重却有显著抑制作用,且La的抑制作用均大于Zn;白菜幼苗叶绿素及可溶蛋白质含量随两离子浓度的升高均呈先升后降的趋势,两指标对La较Zn更为敏感;CAT和POD的活性随La、Zn浓度的增加逐渐上升,而SOD活性则先降后升;两金属离子均能显著地刺激白菜幼苗叶内O2-·大量产生以及MDA迅速积累。[结论]在高浓度下,La表现出比Zn更强的毒性。由此可见,稀土元素La同重金属元素Zn对白菜的毒害机制相似。从长远来看,稀土La有可能是一种新型污染物。

英文摘要：

[Objective] The aim of this study was to explore the physiological and biochemical responses of Chinese cabbage to La and Zn. [Method] The effects of La and Zn on seed germination and seedling growth were explored by tissue culture method. [Result] La and Zn had little effects on seed germination rate, but significantly inhibited the growth of root and seedling, decreased their fresh weight at higher concentration; the inhibition of La proved higher on Chinese cabbage. The contents of chlorophyll and soluble protein increased at lower concentrations of La and Zn, but decreased at higher concentrations. With increasing doses of La and Zn, the activities of CAT and POD rose gradually, while SOD activity decreased at lower doses and increased at higher doses. Both of La and Zn would promote Of. producing and MDA accumulation. [Conclusion] In higher concentration, La was more poisonous than Zn. It is clear that the poisonous mechanism of La is similar to that of Zn. Hence, La is possibly a kind of new pollutant.