Effects of heavy metal-chromium on the DNA methylation in wheat Seedling | 重金属铬对小麦DNA甲基化水平的影响__

chinois. ［目的］研究Cr6+对小麦幼苗DNA含量和DNA胞嘧啶甲基化的影响。［方法］用浓度5~100 mg/L Cr6+分别处理3和10 d龄小麦幼苗后，以CTAB法提取叶片和根系DNA，用紫外分光光度法测定DNA含量，高效液相色谱法进行5-甲基胞嘧啶百分含量的测定。［结果］Cr6+导致小麦幼苗叶片和根系DNA含量显著降低，其中根系DNA含量下降的幅度大于叶片；3 d龄幼苗叶片和根系DNA含量下降的幅度大于10 d龄幼苗。除浓度100 mg/L Cr6+导致3 d龄幼苗根系DNA胞嘧啶甲基化水平的降低外，所试浓度Cr6+均引起了3和10 d龄小麦幼苗叶片和根系DNA胞嘧啶甲基化水平的升高。［结论］Cr6+处理引起不同苗龄小麦幼苗DNA含量和DNA胞嘧啶甲基化水平的改变，可能是影响小麦幼苗正常生长的原因。

anglais. ［Objective］ In this article，the effect of Cr6+ on the content of DNA in wheat seedling and its methylation was studied. ［Method］ The content of DNA in leaf and root of 3-10 day-day wheat seedlings, which were treated with Cr6+ with the concentration of 5-100 mg/L, was tested with the method of UV spectrophotometry and the percentage of 5-MeC was tested with the method of liquid chromatography. ［Results］ The results indicated that The treatment of Cr6+ caused the marked reduction in the content of DNA in root and shoot of wheat seedling and the declining extent of DNA in root was bigger than that in shoot and the declining extent of DNA in the shoot and root of 3-day-old seedling was still bigger than that of 10-day-old seedling. The content of DNA cytosine methylation in shoot and leaf of both 3 day-age and 10-day-age seedling in the treatments of Cr6+, except the 100 mg/L of Cr6+in the root of 3 day-old seedling, were raised. ［Conclusion］ The treatment of Cr6+ resulted in the variation of the DNA content in the wheat seedling with the different day-olds, which could be main reason affecting the normal growth and development of wheat seedling._