Classification of the antioxidant defense system as the ground for reasonable organization of experimental studies of the oxidative stress in plants

A specialized system for antioxidant defense prevents damaging effects of reactive oxygen species (ROS) in the cells of plants and other organisms. The components of this system are numerous and diverse. Repeated attempts were taken to classify these components, which, however, did not result in the creation of unique and commonly accepted classification. In the last few decades, a great body of information concerning antioxidants (AO) has been accumulated, and it demands classification. Today this demand is especially urgent: such classification of the system of AO defense would generalize and systematize the available knowledge of AO and the system of AO defense as a whole and also helps in more efficient and purposeful studying the mechanisms of organism defense against unfavorable factors accompanied by ROS generation. This review discusses the purposeful of the reasonable classification of the AO defense system; we present several examples of current classifications and suggest our resolution of this problem.