低氧胁迫下钙对樱桃砧木根系抗氧化系统及线粒体功能的影响

Effect of Calcium on the Functions of Antioxidant Systems and Mitochondria in Cherry Rootstock Roots Under Hypoxia Stress

【目的】探讨低氧胁迫下钙对樱桃幼苗根系抗氧化系统及线粒体功能的影响。【方法】通过溶氧调节仪人为控制营养液溶氧浓度为2mg·L-1,钙离子浓度设4个梯度:A(0)、B(2.5mmol·L-1)、C(5mmol·L-1)、D(10mmol·L-1)。以1/2Hogland营养液水培并正常通气处理作对照。【结果】与对照相比,各处理的SOD、POD、CAT酶活性在处理前期均受到诱导,随处理时间的延长酶活性下降;线粒体中H2O2、MDA含量提高、生成速率上升;营养液缺钙处理SOD、POD、CAT酶活性降低最快,而线粒体中H2O2、MDA含量、生成速率最高,营养液加钙处理可以在较长时间内维持较高的SOD、POD、CAT酶活性,降低活性氧的产生及MDA含量,提高线粒体氧化磷酸化水平,从而缓解低氧伤害,且10mmol·L-1钙离子处理比5mmol·L-1钙离子处理缓解低氧伤害的作用更明显。【结论】营养液适量加钙可以缓解低氧胁迫对樱桃砧木根系的伤害。

[ Objective ]The purpose of this paper is to explore the effects of exogenous application of calcium to nutrient solution on the function of antioxidant systems and mitochondria in cherry rootstock roots under hypoxia stress. [Method] The cherry rootstock seedlings were cultured in 1/2 Hogland nutrient solutions of different Ca2＋ concentrations （A： 0; B： 2.5 mmol·L^-1; C： 5 mmol·L^-1; D： 10 mmol·L^-1）. The dissolved oxygen concentration of nutrient solution was controlled in 2 mg·L^-1. The treatment of control was aerated and Ca^2＋ concentration was 2.5 mmol·L^-1. [Result] Compared with the control, the activities of SOD, POD and CAT in the four treatments were all increased at first and then decreased. The content of H2O2 and MDA, production rate of O2 in mitochondria of cherry rootstock roots under hypoxia stress were increased. The decreased activities of SOD, POD and CAT in the treatment of calcium deficiency were the fastest and the content of H2O2 and MDA, production rate of O3 in mitochondria were the most among the four treatments. The results showed that additional calcium in nutrient solution under hypoxia stress increased the activities of SOD, POD and CAT, and decreased the contents of H2O2 and MDA, the production rate of O2, and increased the cytochrome c/a and the rate of respiration of mitochondria by increasing respiratory control ratio （RCR） and oxidative phosphorilation ratio （P/O）. [Conclusion ] The above results suggested that exogenous application of calcium in nutrient solution could antagonize the damage of hypoxia stress on cherry rootstock seedlings.