EN
In this study, we used poplar as a model plant and investigated the effects of gaseous nitrogen dioxide (NO2, 4 ll 1-1) on stomatal conductance, photosynthesis, dark- and photorespiration of Populus alba 9 Populus berolinensis hybrid leaves using the photosynthesis system and scanning electron microscope technique. The results showed that net photosynthetic rates were significantly reduced in leaves exposed to 4 ll 1-1 NO2 for 48 h as compared with leaves exposed to ambient carbon dioxide 380 ll 1-1 and ambient NO2\0.1 ll 1-1 (the control) and the leaves exposed for 14 h. The decline of net photosynthetic rate was caused mainly by NO2 treatment. Dark respiration rates were dependent on co-action of the two factors (leaf temperature and NO2 treatment time). Postillumination carbon dioxide burst in the exposed leaves occurred at 13–15 s after turning the light off, whereas this phenomenon was absent in the control leaves.