The relationship between reactive oxygen species and nitric oxide in ultraviolet-B-induced ethylene production in leaves of maize seedlings

The roles of reactive oxygen species (ROS) and nitric oxide (NO) in ethylene synthesis induced by UV-B radiation (280–320 nm) in Maize (Zea mays L. Yuyu No. 22) seedlings were investigated. UV-B radiation resulted in the increase in ROS, NO and ethylene production. Repression of the UV-B-induced ethylene by inhibitors of ethylene synthesis did not affect the accumulation of UV-B-induced O2−, H2O2 and NOS. In contrast, scavenging UV-B-induced O2−, H2O2 and NO production resulted in the repression of UV-B-induced ethylene. Furthermore, exogenous O2− and NO promoted the UV-B-induced ethylene accumulation. The results indicated that ROS and NO played an important role in UV-B-induced ethylene synthesis in maize seedlings. Experiments with related inhibitors suggested that NO was originated from NOS, not from NR, and ROS was not from NADPH oxidase. A synergistic effect in promoting the accumulation of UV-B-induced ethylene between NO and ROS (mainly O2−) was found.