水分胁迫下湖北海棠根系线粒体及细胞死亡特性研究

用20% PEG6000处理湖北海棠(Malus hupehensis Rehd. ) 根系, 研究了水分胁迫条件下根系线粒体膜电位(Δψm) 、线粒体H₂O₂含量、细胞程序性死亡关键酶类caspase23 /7活性的变化。结果显示,在20% PEG6000处理前6 d, 根系线粒体Δψm缓慢降低, 第6天后急剧下降。线粒体H₂O₂含量在处理的第1～6天里缓慢升高, 第6天后则快速上升。TUNEL原位检测显示, PEG6000处理能够使根系切片上出现清晰的阳性反应斑点, 且随着处理时间的延长阳性反应斑点增多; 处理第3天和第6天, 根系中类caspase23 /7活性较低, 而处理第9天和第12天时类caspase23 /7活性成倍升高, 这表明20% PEG6000能够诱导湖北海棠根系细胞程序性死亡。

Study on Root Mitochondrial Characteristics and Root Cell Death of Malus hupehensis Rehd. under Water Stress

The changes of root mitochondrial membrane potential (Δψm), H2O2 concentration and the activity of caspase-3/7, the key enzyme of programmed cell death were studied under 20%-PEG6000 treatment. The results showed that root mitochondrial Δψm declined slowly in the first six days of PEG treatment, then declined rapidly. The content of mitochondrial H2O2 increased slowly in the first six days, then accumulated speedy inside of mitochondria. TUNEL assay was carried out and root paraffin slices displayed distinct positive reaction spots, which were more and more with the prolonging treatment. The activity of caspase-3/7 in root kept at low level from the first day to the sixth day, and then rose sharply on the ninth and twelfth day of PEG treatment. These indicate that 20% PEG6000 can induce programmed cell death in Malus hupehensis Rehd. roots at a certain treating-phase.