Abstract: In order to explore the effects of Pb and Zn combination  on tobacco antioxidant enzymes and carbon-nitrogen metabolism, this paper used flue-cured tobacco Honghuadajinyuan as tested variety, and investigated the effects of different concentration Pb (0, 150, 450, 750 mg·kg^-1) and Zn (0, 20, 60, 100 mg·kg^-1) on the activity of superoxide dismutase(SOD), peroxidase(POD), nitrate reductase (NR) and sucrase, and contents of malondialdehyde (MDA), proline, protein and soluble sugar of tobacco leaf by two-factor factorial experiment under soil culture. The results showed that: single Pb and Zn displayed low concentration promotion and high concentration inhibition on tobacco antioxidant enzyme activity and carbon-nitrogen metabolism. Zn and Pb were the main influencing factors of tobacco leaf sucrose enzyme and POD activity, respectively. The interaction of Pb×Zn showed significant effects on the antioxidant system and carbon-nitrogen metabolism of tobacco. The low or middle concentration of Pb and Zn interaction produced the antagonistic effect on tobacco, activated the antioxidant enzymes and promoted the carbon and nitrogen metabolism. Moreover, when one metal element concentration was higher and the other was lower, Pb and Zn combination also had  synergistic effect, which inhibited the antioxidant enzymes activity and carbon-nitrogen metabolism, and aggravated heavy metals toxicity to tobacco.

Key words: flue-cured tobacco, heavy metal, combination effect, antioxidant enzymes, carbon and nitrogen metabolism

摘要： 为探讨Pb、Zn复合作用对烟草抗氧化酶及碳氮代谢的影响，以红花大金元为供试烟草品种，采用土培双因素析因试验考察了不同浓度的Pb（0、150、450、750 mg·kg^-1）和Zn（0、20、60、100 mg·kg^-1）复合作用对烟叶中超氧化物歧化酶、过氧化物酶、硝酸还原酶和蔗糖酶活性及丙二醛、脯氨酸、蛋白质和可溶性糖含量的影响。结果表明：单一Pb、Zn处理对烟叶抗氧化酶活性及碳氮代谢指标均表现为低浓度促进，高浓度抑制。Pb×Zn交互对烟叶的抗氧化系统和碳氮代谢影响显著。Zn、Pb分别是烟叶蔗糖酶、过氧化物酶活性的主要影响因素。中低浓度Pb与Zn交互对烟草的影响表现为拮抗作用，激活抗氧化酶，碳氮代谢增强；而当一元素浓度过高，另一元素浓度较低时，则会产生协同效应，抑制烟叶的碳氮代谢及抗氧化酶活性，加剧对烟草的毒害程度。

关键词: 烤烟, 重金属, 复合作用, 抗氧化酶, 碳氮代谢