中文摘要：

采用DNA吸收光谱法和蚕豆微核试验，研究了毒死蜱、氰戊菊酯和马拉硫磷3种农药对小牛胸腺DNA和蚕豆根尖细胞的损伤作用。结果表明，这3种农药均能使得小牛胸腺DNA吸收光谱在207nm处的吸收峰出现红移现象，随着药剂浓度的增加，谱图出现了减色效应，说明这3种农药可能对DNA有潜在的损伤作用。微核试验结果表明，3种农药在设定的浓度范围内，随着浓度的增大，微核率均随之升高，当农药的剂量达到10μg·mL^-1时，微核率与对照相比均有极显著差异（P〈0．01）。表明这3种农药达到一定剂量后会对蚕豆根尖细胞的DNA造成遗传损伤。

英文摘要：

To study the effect of chlorpyrifos, fenvalerate and malathion on the calf thymus DNA and Viciafaba root tip cells, DNA absorption spectrophotometry and micronucleus test were employed in the experiment. Formation of DNA adducts may serve as an indicator of DNA damager. Detection of binding of chlorpyrifos, fenvalerate and malathion with calf thymus DNA was based on a shift of DNA absorption spectrum. The results showed that the three pesticides resulted in the displacement of absorption peak （207 nm） moving to long wavelength for calf thymus DNA. The displace activities gradually increased along with the increase in concentration. The three pesticides also caused hypochromic effects of the DNA. These phenomenas indicated that pesticides were bound with DNA and had caused the potential trauma to DNA. If these DNA adducts are not repaired or misrepaired before cell duplication ,the gene mutation and chemical damage would happen. In the micronuclei test, the results showed that with a certain concentration ,micronuclei rate increased as the concentrations increased. At the low dose （0.1 μg·mL^-1）, there were no effect on the micronuclei rate ,compared with the negative controlled group （P〉0.05）.But there were adverse effects when the dose increased,and the difference was significant as compared with the negative controlled group （P〈0.01）.These three pesticides with a certain concentration had significant effects on cytogenetical toxicity of Viciafaba root tip cells.