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[目的]研究施氮量对烤烟烟叶抗氧化系统及质量的影响。[方法]以K326为试验材料,对不同施氮水平烤烟生长成熟期间烟叶活性氧含量、SOD活性、GR活性、APX活性、抗氧化剂含量、化学成分进行了研究。[结果]随着烟叶在田间的生长成熟,烟叶内超氧阴离子产生速率、过氧化氢的含量呈增加趋势;抗氧化酶活性整体呈先上升后下降的趋势;抗氧化剂GSH逐渐下降;As A含量在生长前期逐渐增加,但生长后期逐渐下降。不同施氮水平对烤烟烟叶生长成熟期间抗氧化系统有显著影响。在高氮水平下,烟叶内活性氧清除系统中的自由基清除剂(GSH、As A)和相关酶活性(SOD、GR、APX)均显著或极显著高于低氮水平处理。随着施氮量的增加,烤后烟叶含氮化合物显著增高,蛋白质、淀粉、叶绿素和类胡萝卜素等大分子物质降解量减少,石油醚提取物显著减少,但对钾和氯影响不显著,烟叶质量降低。[结论]烤烟大田管理中适量施氮(45.0 kg/hm2)有利于烟叶生长前期保持较高抗氧化活性,抵御胁迫,在成熟期确保适时成熟,提高烟叶质量。
[Objective] The research aimed to study the effects of nitrogen rate on anti-oxidation system and quality of flue-cured tobacco leaves. [Method] With K326 as test material, the active oxygen content, SOD activity, GR activity, APX activity, antioxidant content and chemical composition of tobacco during the ripening period were studied. [Result] With the maturing of tobacco leaves in the field, the content of superoxide anion and the content of hydrogen peroxide in tobacco leaves increased. The activity of antioxidant enzymes increased firstly and then decreased. The content of antioxidants GSH gradually decreased. As A The content gradually increased in the early growth stage, but gradually decreased in the late growth stage. Different levels of nitrogen fertilizers have significant effects on the antioxidant system during the growth of flue-cured tobacco leaves. At high nitrogen level, free radical scavengers (GSH, As A) and related enzyme activities (SOD, GR, APX) in the active oxygen scavenging system were significantly or extremely significantly higher than those under low nitrogen levels. With the increase of nitrogen application rate, the content of nitrogenous compounds in the cured tobacco leaves increased significantly, the degradation of macromolecules such as protein, starch, chlorophyll and carotenoids decreased, the petroleum ether extract decreased significantly, but the effect on potassium and chloride was insignificant, Tobacco quality is reduced. [Conclusion] The suitable amount of nitrogen application (45.0 kg / hm2) in flue-cured tobacco field management was beneficial to maintain high antioxidant activity of tobacco leaves at early growth stage and to resist stress, to ensure timely maturity at maturity and to improve the quality of tobacco leaves.