Effects of Ozone Stress on Secondary Metabolism and Antioxidant Capacity in Soybean Roots

Abstract

In this paper, to examine the effects of elevated ozone on secondary metabolism and antioxidant capacity in soybean roots, as well as reactive oxygen species and antioxidant enzymes activity. Soybean grown in open top chambers (OTCs) were exposed to ambient air ([O 3 ]=40nmol•mol-1) and elevated ozone ([O 3 ]=110±10nmol•mol-1). The results revealed that with ozone concentration rising, compared with control, the O 3 stress induced the total flavonoids content in soybean root of all treatments showed a significant rising trend (P<0.05), and the total polyphenols content showed a rising trend but not significant. The PAL and PPO activity of soybean root was always lower than that of CK, the LOX activity of soybean root was always higher than that of CK, but the PALˎLOX and PPO activity of soybean root expressed an increased trend with the increase of soybean growth period. However, variation of antioxidant enzymes activity in soybean roots was very different from each other. Superoxide dismutase (SOD) activity was lower than the CK treatment at flowering and podding stages under elevated ozone stress, it presents a volatility changes. During the whole growth stage, elevated ozone stress induced a decrease on activity of catalase (CAT) except for flowering stage, it had a significant increase (p<0.05), the ozone treatment was higher than the CK treatment in general except flowering stage. Activity of peroxidase (POD) was increased under elevated ozone. It had a higher representation (p<0.05) than the CK treatment at every stage. It can be concluded that the ozone stress has significant effects on soybean roots, and effects on soybean roots' normal growth.

Reactive Oxygen Species Metabolism and Diacetoxyscirpenol Biosynthesis Modulation in Potato Tuber Inoculated with Ozone-Treated Fusarium sulphureum

“…In this study, we found that O 2 •production rate in potato tubers inoculated with ozonetreated F. sulphureum was higher than that of the control group, and a similar trend was found in H 2 O 2 content (Figure 3), indicating that ozone treatment activated ROS metabolism through increasing O 2 •production rate and H 2 O 2 accumulation. These findings are consistent with the report of Zhao et al [31], who suggested that ozonetreated soybean roots led to higher O 2 •production rate and H 2 O 2 content than the control group, which was ascribed to ozone-induced oxidative stress. O 2 •mainly comes from NOX that can reduce oxygen molecules into superoxide anion through NADPH-dependent single electron reduction, thereby regulating the production of superoxide anion, which is the main source of ROS in the cell and the only enzyme that directly produces ROS in the cell [18].…”