关键词: 稀土元素, 氧化钬, 有丝分裂指数, 染色体畸变分析, 微核

Abstract: Crystal of nitrate,made by the reaction of holmium trioxide and nitric acid,was dissolved in distilled water,thus diluted into gradient solution.Soaked in the solution for 6 hours（6h）,The root tips of Vicia faba were then recovered and cultivated for 22h and 24h,respectively.By observing the change of root tips and calculating the frequency of micronucleus (FMN),the frequency of chromosomal aberrations(CAF) and mitosis index(MI),we find that the dosage below 4mg/L(expressed by concentration of holmium trioxide)could accelerate the growth of root tips of Vicia faba.CAF and FMN increased while MI decreased with the rise of concentrations.From it a dosageeffect relationship is clearly seen.And it indicated that the rareearth element holmium has certain cytotoxic and genotoxic effects.Furthermore,the different recovery groups have different FMN,CAF and MI,and the difference lies in the fact that FMN of 22hrecovery group was lower than that of 24hrecovery group,while CAF and MI were higher than those of 24hrecovery group.The results suggest that the statistics of FMN should be made after that of CAF.