Abstract
Peroxyacetyl nitrate (PAN), a photochemical oxidant, is one of the most toxic components among common air pollutants and causes severe injury on plant leaves. Petunia leaves are known to show a change from PAN tolerant to sensitive and back to tolerant again, depending on the maturation progress. It has been proven that superoxide accumulates before PAN injury appears, and hydrogen peroxide accumulates in injured leaves. The present study was carried out in order to clarify the role of reactive oxygen species (ROS) and antioxidative enzymes in PAN injury.
PAN injury was restricted under anaerobic conditions, confirming the participation of ROS in the development of the injury. Moreover, POX activity was not only in parallel with the age-dependent rise in tolerance against PAN, but also correlative to the difference in sensitivity between assorted varieties of petunia, suggesting the importance of the scavenging enzymes in the attainment of tolerance against PAN.
