抗氧化系统参与不同抗性烟草品种幼苗对干旱和低温综合抗性的形成

Involvement of Antioxidant Defense System in Drought and Chilling Comprehensive Resistance Formation in Different Resistant Varieties of Tobacco Seedlings

以对干旱和低温胁迫具不同抗性的两个烟草品种MSK326和云烟203为材料,研究了抗氧化系统在不同抗性烟草品种幼苗对干旱和低温综合抗性形成中的作用。在干旱和低温胁迫下,MSK326的存活率均显著高于云烟203,并具较低的叶片电解质渗漏率和丙二醛含量,显示了较强的综合抗性。对细胞抗氧化剂和抗氧化酶的测定显示,在干旱和低温胁迫下,MSK326幼苗中还原型抗氧化剂AsA、GSH含量及其在总抗氧化剂中的比例,以及重要的抗氧化酶SOD、CAT、POD、APX的活性均高于云烟203,并且在胁迫后期差异尤为明显。上述结果表明,MSK326在胁迫下具较强的氧化还原能力,有助于减轻干旱和低温胁迫引发的氧化损伤,抗氧化系统参与了两个抗性不同的品种对干旱和低温胁迫综合抗逆性的形成。

Two varieties of tobacco with different drought/chilling-resistance, MSK326 and yunyan203, were taken as experimental materials in this study, aiming at understanding the involvement of antioxidant defense system in drought and chilling comprehensive resistance formation of tobacco seedlings. MSK326 had a higher viabillity than yunyan203, with a lower relative electrolytic leakage and MDA content of leaves under both drought and chilling stress, demonstrating a higher comprehensive resistance to drought and chilling stress than yunyan203. The resuhs of cellular antioxidant contents and enzymatic activity determination showed that, under drought or chilling stress, MSK326 could retain higher contents of AsA and GSH, ratio of reduced to total antioxidants and activities of the antioxidant enzymes （ SOD, CAT, POD, APX ） than yunyan203, especially at the late stage of stress. All these results indicated that an enhanced intracellular anti-oxidative capacity of MSK326 could be helpful to alleviate stress-induced oxidative damages, indicating the involvement of antioxidant system in drought and chilling comprehensive resistance formation of tnbaco seedlings.