LAUSR

To investigate the physical and ecological effect of chromones in the plant upon high-temperature, the fresh root of Saposhnikovia divaricata (Turxz.) Schischk. were exposed to high-temperature stress (30, 40, and 50°C) for 0, 3, 6 days, and the activity of antioxidant enzymes and PAL, the content of H2O2 and chromones were determined. The results showed that under high-temperature stress, the content of H2O2 and chromones were significantly increased, along with increased peroxidase and PAL activity, whereas the activity of SOD and catalase was decreased. DPPH clearance test demonstrated that chromone itself had no capacity to scavenge ROS. However, its H2O2 eliminating effect was significantly enhanced in the presence of peroxidase. Chromones are the main substance mediating the resistance of S. divaricata to ambient stress. The content of those secondary metabolites showed consistent trend with peroxidase activity, and they together participate in the clearance of ROS.