ROS were considered as unavoidable by-products of aerobic
metabolism (Dat et al., 2000). The ROS production in plant tissue is
low under normal condition, but wounding stress can disorder the
homeostasis in cells, enhance the respiration rate and trigger other
sources of ROS such as amine oxidases and NADPH oxidases,
leading to the increase of ROS production in the site or adjacent of
wounded cells (Mittler, 2002).