铝胁迫对烟草叶片呼吸作用和活性氧代谢的影响

Effects of Aluminum Stress on Respiration and Reactive Oxygen Metabolism in Leaves of Tobacco Seedlings

以2个不同耐铝性的烟草品种云烟100(耐铝)和云烟105(敏感)为材料,采用水培法研究不同铝浓度(0,50,100,200μmol/L)对烟草植株生长、叶片活性氧(ROS)含量、呼吸作用和线粒体抗氧化酶活性的影响。结果表明:随铝浓度的增加,烟草植株生物量显著下降,叶片O·-2和H2O2含量显著升高且敏感品种云烟105变幅更明显,表明烟草铝毒害与叶片ROS积累呈正相关。随铝浓度的增加,烟草叶片总呼吸、细胞色素呼吸和细胞色素氧化酶(COX)活性不断下降,而交替呼吸和丙酮酸含量先升后降,表明铝胁迫下烟草各呼吸途径的变化与COX活性受抑及丙酮酸对交替氧化酶活性的正向调控有关。铝胁迫下烟草叶片线粒体超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性显著升高,有利于清除细胞内产生的ROS。与敏感品种云烟105相比,耐铝品种云烟100在不同铝浓度胁迫下均表现出更高的交替呼吸、总呼吸、线粒体SOD和APX活性,说明铝胁迫下烟草叶片保持较高的呼吸作用(尤其是交替呼吸)以及线粒体SOD和APX活性与其抗铝性密切相关。

Two different aluminum（ Al）-tolerant tobacco cultivars Yunyan 100（ Al-tolerant） and Yunyan105（ Al-sensitive） were used to study the effects of four Al concentrations（ 0,50,100,200 μmol / L） on plant biomass,leaf reactive oxygen content and respiration,activities of antioxidant enzymes in mitochondria.The results showed that the plant biomass decreased significantly,and the leaf O·-2and H2O2 contents increased significantly with the increase of Al concentrations,which was more obvious in Al-sensitive cv. Yunyan 105,suggesting that Al phytotoxicity was positively related to leaf reactive oxygen（ ROS） accumulation. With the Al concentrations increased from 0 to 200 μmol / L,leaf total respiration,cytochrome respiration and cytochrome c oxidase（ COX） activity decreased steadly,while alternative respiration and pyruvate content were promoted firstly and then reduced again,indicating that inhibition of COX activity and promotion of pyruvate content explained the changes in different pathway respiration in tobacco under Al stress. Meanwhile,Al significantly increased the activities of superoxide dismutase（ SOD） and ascobate peroxidase（ APX） in mitochondria,contributing to elimination of intracellular ROS.Compared with Al-sensitive cv.Yunyan 105,Al-tolerant cv.Yunyan100 remained higher alternative respiration,total respiration,activities of SOD and APX in mitochondria under different Al concentrations.These results indicated that higher Al tolerance of tobacco is associated with the capacity to keep high respiration,espcially alternative respiration,and activities of SOD and APX in mitochondria under Al stress.