Abstract: The effects of light and nitrogen level on the exchanges of NOx (NO,NO2 ) in rice (Oryza sativa L.) phyllosphere at the tillering stage and the mechanism were studied by using chamber method and online examination system. There were significant effects of NO emission and NO2 uptake in rice phyllosphere, the mean rates of NO emission and NO2 uptake were 2.48 and 0.116 μg/(pot·h) under the light density regulated strictly in a growth chamber (L1 treatment), and were 2.84 and 0.175 μg/(pot·h) under without light controlling in laboratory(L2 treatment), respectively. Further more, NO emission was also occurred ever if the NO content of ambient air exceeded 200 μg/m3. Without light controlling in laboratory, NO emission from rice plant significantly increased in 0-5 days after nitrogen application, and then decreased gradually. Followed with the rate of nitrogen increased from 0 to 80 mg/L NH4NO3N, NO emission increased as a whole, but was not decreased significantly under no nitrogen nutrient or low level of N (10 mg/L NH4NO3N) in shortterm ( 0-7 days). The rate of NO2 uptake was also promoted under the increasing nitrogen (0-60 mg/L NH4NO3N). In shortterm (1-2 days) after nitrogen application, the effects of NOx emission in rice phyllosphere from the time at low light density (6:00-10:00) to the time at high light density (10:00-14:00) were stimulated by favorable illumination in the growth chamber, but inhibited evidently from illumination incessantly with strong light at 14:00-18:00. However, both NO emission and NO2 uptake in rice phyllosphere could also be restrained accordingly with the time of darkness prolonged at night. And, there was increasing of NO2 uptake with the time of light illumination prolonging, but NO2 uptake was not affected evidently by the change of light density at daytime. Moreover, both NO emission and NO2 uptake were enhanced when the air of chamber displaced by ambient air continuously in laboratory.

Key words: rice (Oryza sativa), light, nitrogen application, nitrogen oxide, nitrogen dioxide, emission, uptake

摘要： 采用密闭箱法结合快速在线检测系统，研究了光氮对分蘖期水稻叶际NOx(NO、 NO2 )交换的作用机制。结果表明：1）在叶际NOx(NO、 NO2 )交换过程中，试验用水稻品种有显著NO净挥发和NO2净吸收效应； 在严密控光和室内自然光条件下，水稻NO净挥发速率分别为2.48和2.84 μg/(桶·h)，NO2 净吸收速率分别为0.116和0.175 μg/(桶·h)，且在环境空气NO浓度为200 μg/m3 条件下也能挥发NO。 2）更换营养液后观测期(5 d)水稻NO挥发速率呈先升后降趋势，在供N 0~80 mg/L范围内提高供氮水平总体上增强了水稻NO挥发，但短期内（7 d）脱氮、缺氮(供N 10 mg/L)无明显抑制水稻NO挥发的作用；同期适度提高供氮浓度(供N 0~ 60 mg/L)增强了水稻NO2 吸收，但供氮6 d后外源氮源对水稻叶际NOx(NO、NO2 )交换的调控作用明显下降;3）更换营养液后短期内(1~2 d)控光处理下 6：00-10：00弱光和10：00-14：00 强光有刺激水稻NOx(NO、NO2 )挥发的作用，但14：00-18：00持续强光明显抑制了水稻NOx挥发；在更换营养液2 d后，延长光照时间能增强水稻NO2吸收，但光强变化对水稻NO2吸收调控作用不明显，晚上暗处理有同步抑制水稻NO挥发和NO2吸收效应;4）与基本不置换培养箱空气处理相比，置换培养箱空气同步增强了水稻NO挥发和NO2吸收。

关键词: 水稻, 光照, 氮素, 一氧化氮, 二氧化氮, 吸收, 挥发