【摘要】 研究了活性氧在UV-B(280~320 nm)诱导的玉米(Zea mays)幼苗叶片乙烯合成中的作用。结果表明,UV-B促进了玉米幼苗活性氧和乙烯的产生;乙烯合成抑制剂氨氧乙烯基甘氨酸(AVG)和氨氧乙酸(AOA)能明显减弱UV-B对玉米幼苗乙烯产生的诱导作用,但对活性氧(ROS)的产生没有明显影响;ROS的清除剂不但能抑制UV-B诱导的ROS的产生,而且还可以抑制UV-B诱导的乙烯的产生,但这种抑制作用可以被外源O-.2的供体所逆转。这说明,乙烯的积累不能作为UV-B胁迫下ROS的诱导的因素,相反,ROS的积累则导致了乙烯的积累;因此,ROS可能参与了UV-B胁迫诱导的乙烯的产生。质膜NADPH氧化酶的抑制剂二苯碘(DPI)和H2O2的特异性清除剂过氧化氢酶(CAT)对UV-B胁迫诱导的乙烯积累几乎没有影响,这说明H2O2可能与UV-B诱导的玉米幼苗叶片乙烯的产生无关,在UV-B诱导的玉米幼苗叶片乙烯的生物合成过程中O-.2起着很重要的作用,相关的O2.-不是由NADPH氧化酶催化产生的。更多还原

【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 species(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 O-·2 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,O-·2 plays an important role in UV-B-induced ethylene synthesis in leaves of maize seedlings and O-·2 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.更多还原