以普通大麦幼苗为材料,用除草剂、光合电子传递链抑制剂、H2O2、活性氧清除剂、强光或叶绿素合成前体物质浸根处理,通过过氧化氢和超氧阴离子染色和rbcS基因Northern杂交检测,研究了活性氧在大麦叶绿体信号传导中的作用.结果显示:除草剂20μmol/L norflurazon(NF)处理明显造成大麦幼苗活性氧染色加重和rbcS基因受抑制,同时用活性氧的清除剂处理可以部分逆转rbcS基因的下调;光合电子传递链的抑制剂也明显造成活性氧染色加重和rbcS基因受抑制,同时用活性氧的清除剂处理可以完全逆转rbcS基因的下调;光合电子传递链抑制剂对糖饥饿诱导的rbcS基因上调有抑制作用,同时用活性氧的清除剂处理可以完全逆转此抑制作用;高浓度糖或叶绿体蛋白质合成抑制剂都不能引发活性氧,但可以显著抑制核编码光合基因.可见,除草剂NF引发的信号是镁原卟啉信号与活性氧信号的叠加,光合电子传递链的氧化还原状态改变引发的信号绝大部分可以归结为活性氧信号,而高浓度糖和叶绿体蛋白质合成引发的叶绿体信号与活性氧没有直接联系.
The role of reactive oxygen species(ROS) in plastid signaling was studied.Barley roots were treated with herbicide,photosynthetic electron transfer(PET) chain inhibitors,H2O2,ROS eliminators,high light or chlorophyll-biosynthesis intermediates.Then the H2O2 and O-·2 levels were detected by the stain methods and the rbcS transcription levels were detected by Northern blots.The results showed that:the herbicide norflurazon(NF) induced ROS accumulation and rbcS gene down-regulation,which could be half reversed by ROS eliminators,pointing that NF drives not only Mg-protoporphyrin-induced signal but also ROS-induced signal.The PET chain inhibitors also induced both ROS accumulation and rbcS gene down-regulation,which could be completely reversed by ROS eliminators,suggesting that PET redox-derivate signal could be largely regarded as a kind of ROS-induced signal.The effect that PET inhibitors prevent increases of nuclear-encoded photosynthetic genes transcripts in sugar-starved plants could be reversed by ROS eliminators,which also could be attributed to the negative regulations by ROS.High level sugar or plastid protein synthesis inhibitors could not induce any ROS,but down-regulate nuclear-encoded plastid genes,implying that these two signals were not correlated with ROS directly.Meanwhile,the role of ROS in plastid-to-nucleus signaling was discussed.