铝对蚕豆根尖细胞的遗传损伤

Cytogenetic damage induced by aluminum trichloride in Vicia faba root tips

铝作为土壤主要元素之一，是酸性条件下影响植物生长发育的一个主要原因。为进一步探讨酸性条件下铝对植物细胞的毒性作用机理，文章以蚕豆（Hcia faba L．）为材料，研究了不同酸度（pH4．5和pH5．8）的三氯化铝对根尖细胞的遗传损伤作用。结果表明，pH5．8和pH4．5的铝处理（0．03-50mmol·L^-1）组中根尖细胞分裂指数呈浓度依赖性降低，微核细胞数显著增加。相同铝浓度时，pH4．5N的分裂指数低于pH5．8组，微核率高于后者。此外，铝处理能诱发根尖细胞核固缩，固缩率随酸度增强和铝浓度增大而增高。研究结果表明，三氯化铝对蚕豆根尖细胞具有遗传损伤作用，酸性增强时铝的毒性作用增强。

Aluminum （Al） is the most abundant metal of the earth＇s surface, comprising approximately 8% of the earth＇s crust and approximately 7% on average in soils. Aluminum toxicity is one of the major factors that limit plant growth and crop productivity in acid soils. In order to explore the mechanism of toxic effects of acidic aluminum on plant cells, cytogenetic damage induced by aluminum trichloride was studied in Vicia faba root tip cells. Our results showed that aluminum trichloride caused micronuclei formation and mitosis inhibition in a range of 0.03 to 50 mmol·L^-1 at pH 5.8 and pH 4.5. With the same concentrations of aluminum, mitotic indexes were lower at pH 4.5 than those of the treatments at pH 5.8, while the frequencies of micronuclei were higher at pH 4.5. Furthermore, aluminum treatments induced pycnosis dose dependently. The results of the present study indicated that aluminum was genotoxic and lower pH can enhance the toxicity of Al treatments.