环境胁迫不但是植物生长发育、更是农作物产量的主要限制因素，而氧化胁迫在这些环境胁迫中占据重要份额，增强耐氧化性状是改良农作物抗逆性的一个重要方面。氧化胁迫是细胞内活性氧(ROS)积累超出平衡水平的一种次生胁迫，通常是因其它胁迫(生物和非生物胁迫)而导致ROS加速产生而过量积累造成。ROS的过量积累直接对生物膜和生物大分子造成破坏，加速细胞衰老，甚至死亡。所以，细胞内ROS的水平受到严格的监控，过量的ROS被及时的清除。植物在进化过程中形成了有效清除ROS的防卫系统，虽然我们对这些防卫系统已经有了较清楚的认知，但对氧化胁迫信号传导与上游调控机制还知之甚少。此外，越来越多的实验证明，ROS是细胞内众多生命过程的重要信号分子，参与气孔运动的调控，根系生长发育，植物-病原菌相互作用, 细胞程序化死亡等信号传导系统。本课题在获得拟南芥耐氧化突变体的基础上，拟继续解析耐氧化突变体及其相关基因功能。

Environmental stresses not only have great impacts on plant growth and development but also are major constraints of crop yield. Oxidative stress is a secondary stress common and important to all the environmental stresses. Hence improving oxidative stress tolerance is one of the important aspects of crop improvement for stress tolerance. Oxidative stress is generated when the accumulation of cellular reactive oxygen species (ROS) exceeds the normal level. ROS accumulation is accelerated under environmental stresses. Over accumulation of ROS damages membranes and macromolecules, resulting in accelerated ageing and even cell death. Plants have evolved sophisticated ROS surveillance and scavenging systems to keep ROS level under control. Although the ROS scavenging systems are known, the ROS signaling and regulatory mechanisms are not well understood. Moreover, more and more evidence indicate that ROS are signal molecules in many cellular processes such as stomatal movement, root development, plant-microbe interaction, and programmed cell death. The goal of this project is to analyze further the paraquat tolerant mutants that we have isolated and unravel the molecular mechanisms underlying the enhanced tolerance against oxidative stress.