Chin J Plan Ecolo ›› 2007, Vol. 31 ›› Issue (5): 946-951.DOI: 10.17521/cjpe.2007.0120

• Research Articles • Previous Articles     Next Articles

EFFECTS OF REACTIVE OXYGEN SPECIES ON UV-B-INDUCED ETHYLENE PRODUCTION IN LEAVES OF MAIZE SEEDLINGS

WANG Yi-Bo1,2; FENG Hu-Yuan2; QU Ying2; CHENG Jia-Qiang2; WANG Xun-Ling2; AN Li-Zhe2,3*   

  1. 1Department of Biology, Tianshui Normal College, Tianshui, Gansu 741000, China; 2 School of Life Sciences, Lanzhou University, Lanzhou 730000, China; 3 Cold and Arid Region Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Online:2007-09-30 Published:2007-09-30
  • Contact: AN Li-Zhe

Abstract:

Aims Ethylene accumulation and oxidative stress are two common responses of plants to environmental stresses; however, little is known about their relationships. Our objective was to investigate the role of reactive oxygen specie s (ROS) in ethylene synthesis induced by UV-B radiation (280-320 nm) in leaves of maize (Zea mays).
Methods Lamps were suspended above and perpendicular to the plastic trays and filtered with 0.13-mm thick cellulose diacetate (transmission down to 290 nm) for UV-B irradiance. The desired UV-B irradiation was obtained by changing the distance between the lamps and the plastic trays. The levels of UV-B irradiation were 4.8 kJ•m-2•d-1.
Important findings UV-B radiation led to the generation of ROS and ethylene. The accumulation of ethylene induced by UV-B was not only inhibited by the scavengers of ROS, but also by aminoxyacetic acid (AOA) and 2-aminoethoxyvinlglycine (AVG), which are specific inhibitors of ethylene synthesis. The inhibition effect of ROS scavengers on UV-B-induced ethylene production was reversed by O2.- donors. Results indicated that the increase in ethylene production may not be the cause of the increase in ROS production under UV-B stress. In contrast, the increase of ROS led to the accumulation of ethylene.
Results suggested that ROS are involved in UV-B stress-induced ethylene accumulation. The accumulation of UV-B-induced ethylene was not affected by DPI, an inhibitor of NADPH oxidase and CAT, a specific scavenger of H2O2. Results suggested that the effect of H2O2 on UV-B-induced ethylene production in leaves of maize seedlings can be excluded, O2.- plays an important role in UV-B-induced ethylene synthesis in leaves of maize seedling s and O2.- serves as a potential mediator of ethylene production that the plant can sense the UV-B stress. The related ROS are not from plasma membrane NADPH oxidase. The source of ROS contributing to ethylene accumulation under UV-B stress is unknown.