采用密闭箱法结合42 C型 NO-NO₂-NO_X 分析仪的快速线检测系统，在气候箱严密控光（L1）和室内自然光暗处理（L2）条件下，研究了分蘖期水稻地上部和空气间的NO_X（NO, NO₂ ）交换作用，结果表明： 1）试验用水稻品种具有较强的NO挥发能力，在L1、L2条件下水稻NO平均挥发速率 [按鲜质量（g, FW）计算] 分别达到0.0188、0.0239 µg/（g·h），并在环境空气NO浓度达100 µg/m³条件下水稻也能净排放NO；2）水稻能吸收空气NO₂，L1、L2条件下水稻NO₂平均净吸收速率为0.00084、0.00165 µg/（g·h）；3）施氮能增强水稻NO挥发，在气候箱严密控光（L1）条件下，短期内（1～2 d）施氮在日间 6:00～10:00 弱光时段和 10:00～14:00强光时段有刺激水稻NO_X （NO, NO₂ ）挥发的效应， 但在14:00～18:00 时段，持续强光能削弱施氮对水稻NO挥发的刺激作用而增强水稻对NO₂吸收。4）室内自然弱光条件下（L2），施氮能提高日间水稻的NO净挥发速率，水稻NO₂净吸收速率随着有光时间的延长而上升。夜间暗处理条件下，施氮对促进水稻NO的挥发无明显作用，水稻NO₂吸收速率下降。试验结果显示，水稻地上部从空气中净吸收NO₂的平均速率远低于NO净挥发速率，分蘖期水稻地上部分与空气间的NO_X （NO, NO₂ ）交换作用主要表现为NO的净挥发，相当于净损失纯N 10.95～12.5 g/（hm² ·d）。

Using chamber method and 42C NO-NO₂-NO_x gas analyzer with on-line examination system, the exchange of NO_x (NO, NO₂) between above-ground rice plant and ambient air at the tillering stage were studied. The results showed that: 1) There were significant effects of NO emission from above-ground rice plant both in L1 treat with light density regulated strictly by growth chamber and L2 treat without light controlling in laboratory, and the mean rate of NO emission was 0.018 8 and 0.023 9 µg/(g·h) in treatment of L1 and L2, respectively. Further more, NO emission from above-ground rice plant was also occurred ever if the NO content of ambient air exceeded 100 µg/m³. 2) NO₂ was also obviously uptaked by above-ground rice plant, and the net absorption rates of NO₂ in treatment of L1 and L2 was 0.00088, 0.00165 µg/(g·h) respectively. 3) In short-term (1–2 days) after nitrogen application, the effects of NO_X(NO, NO₂)emission from the time of low

light density (6：00–10：00) to the time of high light density (10：00–14：00) was stimulated by nitrogen application under the condition of favorable illumination in growth chamber, but the effect of nitrogen application on NO emission was inhibited evidently by lasting illumination with strong light at 14:00–18:00 time, followed with the increasing of NO₂ uptake by above-ground rice plant at the same time. However; NO emission can not be enhanced from nitrogen application accordingly with the time of darkness prolonged at night, and NO₂ uptake can also be restrained because of darkness at night. 4) Without light controlling in laboratory, there was increasing of NO emission from nitrogen application with the time of weak light illumination prolonged at daytime, when NO₂ uptake decreased at the same time. It can be seen that the rate of NO₂ uptake by above-ground rice plant was far less than the mean rate of NO emission, there were significant effects of net NO-N losses in course of NO_x (NO, NO₂) exchange between above-ground rice plant and ambient air, which was equal to 10.95–12.5 g/(ha·d) NO-N losses at tillering stage of paddy rice according to this study.