赤霉素GA_3急性毒性和遗传毒性

Acute Toxicity and Genetic Toxicity of Gibberellin A_3

目的：研究赤霉素GA3的急性毒性和遗传毒性，为合理使用赤霉素以及赤霉素残留限量标准的制定提供参考。方法：采用最大剂量耐受法测定赤霉素GA3的急性毒性，采用蚕豆根尖细胞微核实验、小鼠骨髓细胞微核实验和小鼠精子畸形实验测定赤霉素GA3的遗传毒性。结果：给昆明种小鼠经口灌胃赤霉素GA3，LD50〉15000mg／kg；赤霉素GA，在质量浓度为0．1～2．0mg／L范围内时，蚕豆根尖细胞微核率呈上升趋势，与阴性对照组相比均存在极显著差异，且微核指数均〉1．5；7．5g／kg赤霉素GA，对雌、雄小鼠的骨髓细胞微核率分别为7．47‰、7．07‰，小鼠精子畸形率为5．47％，与阴性对照组相比均存在极显著差异（P〈0．01）。结论：赤霉素GA3的急性毒性虽然比较低，属于无毒级，但是在较高剂量条件下对植物细胞、动物的体细胞与生殖细胞均具有遗传毒性，应尽快制定赤霉素GA3使用限量标准。

Purpose： To examine the acute toxicity and genotoxicity of gibberellin A3 （GA3）, which can provide scientific support for the reasonable use of GA3 and a reference for establishing maximum residue limit （MRL） for GA3. Methods： Acute toxicity was examined by using the maximum tolerated dose method while genotoxicity was examined using Vicia- micronucleus test, bone marrow cell micronucleus test and sperm abnormality test in mice. Results： The acute oral LDs0 of GA3 in Kunming mice was 〉 15 000 mg/kg. As GA3 concentration increased from 0.1 to 2.0 mg/L, the micronucleus rate of Ficiafaba root tip cells showed a rising trend, which indicated a highly significant difference compared to negative controls and the micronucleus index remained higher than 1.5 at all investigated GA3 concentrations. The bone marrow micronucleus rates of male and female mice treated with 7.5 g/kg GA3 were 7.47‰ and 7.07‰, respectively, and the sperm malformation rate of mice was 5.47%, which revealed highly significant differences compared to that of negative controls （P 〈 0.01）. Conclusion： Although GA3 with low acute toxicity can be considered as a non-toxic substance, it causes genotoxicity to plant cells and animal somatic and germ cells at high doses. The MRL for GA3 should be set up as early as possible.