Rowland A J, Drew M C, Wellburn A R
Department of Biological Sciences, University of Lancaster, Bailrigg, Lancaster LAI 4YQ, UK.
AFRC Letcombe Laboratory, Wantage, Oxon OX12 9TT, UK.
New Phytol. 1987 Oct;107(2):357-371. doi: 10.1111/j.1469-8137.1987.tb00188.x.
The uptake of atmospheric NO through leaf surfaces and the influence on uptake of combined nitrogen by the roots were investigated in hydroponically grown barley plants exposed to 0.3 μI 1 nitrogen dioxide (NO ). The response to NO was dependent on the nitrogen status of the plant at the time of exposure. Only with low nitrate supplies to the roots did exposure of leaves to atmospheric NO cause significant increases in the nitrogen (N) content of barley. Levels of both nitrate and reduced forms of N increased in plants in response to the pollutant and were directly due to uptake of NO by leaves, since the root environment was completely sealed from atmospheric sources of NO . Moreover, these increases were not due to the stimulation of nitrate uptake by the roots from the nutrient solution, although levels of activity of both nitrate and nitrite reductases were affected by exposure to NO . Atmosphere NO did, however, affect the ability of a plant to respond to a change in the amount of nitrate supplied to the roots, and the use of both N-labelled NO and nitrate indicated that the cycling of nitrogen within the plant was also influenced by exposure to atmospheric NO .
在水培大麦植株中研究了通过叶片表面吸收大气中的一氧化氮（NO）及其对根系吸收化合态氮的影响，这些植株暴露于0.3 μl/L的二氧化氮（NO₂）环境中。对NO的响应取决于植株在暴露时的氮素状况。只有在向根系供应低浓度硝酸盐时，叶片暴露于大气中的NO才会使大麦的氮（N）含量显著增加。植株中硝酸盐和还原态氮的含量均因该污染物而增加，这直接归因于叶片对NO的吸收，因为根系环境与大气中的NO源完全隔绝。此外，这些增加并非由于根系从营养液中吸收硝酸盐的刺激作用，尽管硝酸盐和亚硝酸还原酶的活性水平受暴露于NO的影响。然而，大气中的NO确实影响了植株对供应给根系的硝酸盐量变化的响应能力，同时使用¹⁵N标记的NO和硝酸盐表明，植株内的氮循环也受暴露于大气中的NO的影响。
