叶绿体中活性氧的产生和清除机制

Generation and Scavenging of Reactive Oxygen Species in Chloroplasts

正常情况下植物细胞内活性氧(reactive oxygen species ROS)的产生和清除是平衡的,但是,一旦植物遭受环境胁迫,ROS的积累超过抗氧化剂防护系统清除能力,就会产生氧胁迫损伤细胞。由于叶绿体作为光合作用的场所与其他细胞器相比更易遭受氧化胁迫的伤害。因此,叶绿体进化了更强的防御机制调控电子传递链的氧化还原平衡及叶绿体基质中的氧化还原状态。活性氧具有双重效应,高浓度的活性氧对植物细胞有很强的毒害作用,低浓度时可充当信号分子参与植物的某些防卫反应过程,本文就叶绿体中活性氧的产生(三线态叶绿素、PSI和PSII电子传递链)、网络清除(抗氧化剂,SOD,As-Glu循环系统,硫氧还蛋白)机制以及功能作用进行了综述。

Normally, it is balanceable between ROS （reactive oxygen species ）-producing and ROS-scavenging in plant cell. Once reactive oxygen species accumulate under environmental stress to a certain amount that the antioxidant systems in cell cannot eliminate it, it may irreversibly damages cells. Because Chloroplasts are more damageable than other organelles in oxygen stress as a site of photosynthesis, Chloroplasts have developed greater defense system which regulates the redox balance of electron-transport chains and the redox state of Chloropiast Stroma. Reactive oxygen has a dual function that it damages cells at high concentrations and protects cells at low concentrations as a signal molecular. This paper mainly summarized ROS-producing centers （triplet chlorophyll, ETC in PSI and PSI I） and a diversified ROS-scavenging network （antioxidants, SOD, APX-glutathione cycle, and a thioredoxin system） and functions.