Abstract:Our study analyzed the relationship between the different resistant sunflower varieties inoculated with Puccinia helianthi Schw. and the accumulation of active oxygen. H2O2 content and O2- production rate of different sunflower varieties were tested with spectrophotometers; detection of H2O2 and O2-were carried out using the 3,3-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT). The results revealed that in susceptible and resistant varieties active oxygen presented the double peak trends, rapid increment of active oxygen was obvious at the early stage of infection, 16 hours after inoculation (hai), H2O2 and O2- reached to the highest peak; the accumulation of active oxygen in resistant varieties was significantly higher than that in the susceptible. It was observed by in situ stain that in resistant varieties, stain range was wide and deep. The percentage of infection sites showing NBT and DAB staining all reached the highest 65.5% and 41%, respectively, 16 h after inoculation (hai). But no obvious stain was observed in susceptible varieties, suggesting the positive correlation of the accumulation of H2O2 and O2- with the resistance level of sunflower to rust disease.