Since plants are the main source of our food,the improvement of their productivity is the most important task for plant biologists. In this book, leading experts accumulate the recent development in the research on oxidative stress and approaches to enhance antioxidant defense system in crop plants. The book willdiscuss both the plant responses to oxidative stress and mechanisms of abiotic stress tolerance. All of the recent approaches towards understanding oxidative stress in plants will be presented, providing comprehensive information about the topics. Moreover, the cross talk among ROS, RNS and RSS in abiotic stress tolerance will also be presented based on recent research done by experts.