Abstract: The onion root tip was treated with different concentrations of naphthalene acetic acid (NAA) based on 3 μmol·L–1 copper sulfate solution by hydroponics to explore the alleviation effect of NAA on copper stress. The results showed that 3 μmol·L–1 copper sulfate solution significantly inhibited the onion root growth. The combined treatment of 3 μmol·L–1 copper sulfate solution and 1 μmol·L–1 NAA showed double inhibition and increased SOD activity and MDA content of the roots. While the mitotic index of root tip cells decreased significantly, and the aberration rate increased. The treatment with 10–2 or 10–4 μmol·L–1 NAA significantly promoted the growth of onion roots. Under the co-treatment of 3 μmol·L–1 copper sulfate solution and 10–2 μmol·L–1 NAA, NAA significantly alleviated the copper stress on onion roots, and the onion root growth returned to the control level. Compared with 3 μmol·L–1 copper sulfate solution stress, it was found that this treatment significantly increased the mitotic index, and reduced the aberration rate, SOD activity, and MDA content. It was indicated that NAA at appropriate concentrations significantly alleviated the copper stress on root system.

Key words: naphthalene acetic acid; onion root tip; Cu stress; chromosome aberration

摘要： 以洋葱Allium cepa为材料，采用水培方式，以3 μmol·L–1硫酸铜溶液为基础，外加不同浓度萘乙酸，对洋葱根尖进行处理，探究萘乙酸对铜胁迫的缓解作用。结果表明，3 μmol·L–1硫酸铜溶液处理对洋葱根系生长抑制明显；3 μmol·L–1硫酸铜和1 μmol·L–1萘乙酸处理表现出双抑制作用，并提升细胞SOD活性和MDA含量，根尖细胞有丝分裂指数明显下降，变异率增加。10–2或10–4 μmol·L–1萘乙酸溶液处理对洋葱根系生长促进明显。在3 μmol·L–1硫酸铜和10–2 μmol·L–1萘乙酸共处理下，萘乙酸对洋葱根系铜胁迫有明显缓解作用，洋葱根系生长恢复到对照水平，与3 μmol·L–1硫酸铜溶液处理对比，显著提升根尖细胞有丝分裂指数，降低了畸变率、细胞SOD活性及MDA含量。说明适当浓度萘乙酸对根系铜胁迫有明显缓解作用。

关键词: 萘乙酸；洋葱根尖；铜胁迫；染色体畸变