外源甜菜碱及水杨酸对锰胁迫下烟草生理特性的影响

  目的  筛选最佳缓解锰胁迫的外源物质的浓度, 探究其对锰胁迫下烟草生理特性的影响。  方法  采用500 mg/kg的一水合硫酸锰（MnSO₄·H₂O）对盆栽烤烟进行胁迫试验，设置不同浓度的外源甜菜碱及水杨酸进行缓解试验，测定锰胁迫及外源物质作用下烟叶的锰含量、相对电导率及丙二醛含量、抗氧化酶活性、渗透调节物质含量及活性氧产生速率。  结果  锰胁迫下，锰含量、相对电导率及丙二醛含量、抗氧化酶活性、渗透调节物质及活性氧均显著提高，施用外源甜菜碱及水杨酸后以上指标会显著降低。其中，当施用的甜菜碱浓度为0.20 mol/L、水杨酸浓度为150 mg/L时，锰积累量、相对电导率、丙二醛含量及过氧化氢酶活性均达到最低水平，与锰胁迫下的水平达到显著差异；可溶性糖、可溶性蛋白及脯氨酸含量在甜菜碱浓度为0.15 mol/L时达到最低水平。  结论  综合分析表明，当施用的外源甜菜碱浓度为0.20 mol/L、水杨酸浓度为150 mg/L时对烟草锰胁迫的缓解效果较佳。 

Effects of exogenous betaine and salicylic acid on the physiological characteristics of tobacco under manganese stress

  Objective  This study aims to study the effects of exogenous substances on the physiological characteristics of flue-cured tobacco under manganese stress and determine the optimal substance alleviating manganese stress.  Methods  Pot experiment of fluecured tobacco was carried out under 500 mg/kg manganese sulfate stress. Different concentrations of betaine and salicylic acid were used to alleviate the stress. The manganese content, relative electrical conductivity, malondialdehyde content, antioxidant enzyme activity, osmotic regulation substance content and reactive oxygen production rate of flue-cured tobacco leaves under manganese stress and exogenous substances were analyzed.  Results  The results showed that all the indexes increased significantly under manganese stress, and decreased significantly after the application of betaine and salicylic acid. When the concentration of betaine was 0.20 mol/L and the concentration of salicylic acid was 150 mg/L, the manganese content, relative conductivity, MDA content and catalase activity were the lowest, which was significantly different from the levels under manganese stress, and the osmotic regulator reached the lowest level when the concentration of betaine was 0.15 mol/L.  Conclusion  The comprehensive analysis showed that the alleviating effect of manganese stress was better when the concentration of exogenous betaine was 0.20 mol/L and the concentration of exogenous salicylic acid was 150mg/L.