外源H_2O_2对湖北海棠根系线粒体膜透性和细胞核DNA的影响

The Effect of Exogenous H_2O_2 on Mitochondrial Membrane Permeability and Cell Nuclear DNA in Roots of Malus hupehensis

用0.024%(V/V)H2O2处理湖北海棠(MalushupehensisRehd.)实生苗根系,30min后,根系线粒体膜通透性明显增大,线粒体膜电位(?ψm)和线粒体内Cytc/a吸光度比值下降;60min后,根系细胞核DNA发生片段化降解。经荧光染料吖啶橙染色后,可见H2O2处理60min以上的根系压片中出现了清晰致密的黄绿色荧光斑,呈现出细胞程序性死亡(PCD)的特征。

To investigate the changes in mitochondrial permeability transition, DNA degradation and cell death, seedling roots of Malus hupehensis Rehd. were treated directly with exogenous H2O2. The results showed that mitochondrial permeability increased obviously by 0.024% （V/V） H2O2 treatment for 30 min and increased continuously during the time of H2O2 treatment （Fig. 1）. At the time of mitochondrial permeability increasing, mitochondrial membrane potential （△ψm） decreased （Fig.2）. In addition, the ratio of Cyt c/a became lower （Fig.3） when mitochondrial permeability increased and △ψm decreased. DNA fragments were detected at the 60 min of H2O2 treatment, the number of fragments increased after 60 min of H2O2 treatment （Fig.4）. Granular nuclei stained irregularly were evident in root slices stained by acridine orange （Fig.5）. This indicates H2O2 can induce programmed cell death by increasing mitochondrial permeability and decreasing △ψm in the root of Malus hupehensis Rehd.