中文摘要：

为了研究常乐稀土多元复合肥对主要农作物——玉米（Zea mays L．）是否产生细胞毒性和遗传毒性效应，采用不同梯度质量浓度的稀土复合肥溶液对玉米进行处理，观察其根尖生长状况，统计分析细胞死亡率、微核率、有丝分裂指数以及对细胞DNA的损伤情况．结果表明，质量浓度为10mg·L^-1以下时，常乐稀土复合肥能够促进玉米根尖的生长，100mg·L^-1以上时抑制根尖生长；随着试验浓度的递增，细胞死亡率、微核率、DNA损伤率逐渐上升并具有正相关性，表现出明显的剂量-效应关系，而有丝分裂指数却随着浓度的增加逐渐下降．以上结果表明，常乐稀土复合肥对玉米确有一定的细胞毒性和遗传毒性效应，其细胞毒性阈值和遗传毒性阈值皆为100mg·L^-1．

英文摘要：

The root tips were treated with different concentrations of Rare Earth Multi-element Compound Fertilizer （REMECF） in order to evaluate the effect on maize in terms of the growth of root-tip, the mortality, the frequency of micronucleus （FMN） , mitosis index （MI） and DNA damage. The results indicated that the dosage below 10mg·L^-1 （expressed by concentration of RE-MECF） could accelerate the growth of root tips of Zea mays L., but the groups which were treated by the dosages above 100mg·L^-1 were repressed. The mortality, frequency of micronucleus （FMN） and DNA damage increased while mitosis index （MI） decreased with increasing concentrations, from which, the dosage-effect relationship was clearly demonstrated. These results suggested that the RE-MECF had certain cytotoxic and genotoxic effect, and that the cytotoxic and genotoxic threshold dosages were both 100mg· L^-1.