Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China.
Shanghai Engineering Research Centre of Low-carbon Agriculture (SERCLA), Shanghai, 201415, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Sep;25(27):27583-27593. doi: 10.1007/s11356-018-2823-3. Epub 2018 Jul 27.
Nitrogen (N), one of the most important nutrients for plants, also can be a pollutant in water environments. N metabolism is sensitive to N fertilization application and related to rice growth. Different levels of N fertilization treatment (N0, control without N fertilizer application; N100, chemical fertilizer of 100 kg N ha; N200, chemical fertilizer of 200 kg N ha; N300, chemical fertilizer of 300 kg N ha) were tested to investigate N loss due to surface runoff and to explore the possible involvement of rice N metabolism responses to different N levels. The results indicated that N loss through runoff and rice yield was simultaneously increased in response to increasing N fertilizer levels. About 30% of total nitrogen (TN) was lost in the form of ammonium (NH) in a rice growing season, while only 3% was lost in the form of nitrate (NO). Higher N application increased carbon (C) and N content and increased nitrate reductase (NR) and glutamine synthetase (GS) activities in rice leaves, while it decreased glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) activities. These results suggest that N caused the accumulation of assimilation products in flag leaves of rice and stimulated N metabolic processes, while some protective substances were also stimulated to resist low N stress. This study provides a theoretical basis for improving N fertilizer management to reduce N loss and increase rice yield.
氮（N）是植物最重要的营养元素之一，但在水环境中也可能成为污染物。氮代谢对氮施肥应用敏感，与水稻生长有关。本研究设置了不同的氮施肥处理（N0，对照不施氮肥；N100，施 100kg N/ha 化肥；N200，施 200kg N/ha 化肥；N300，施 300kg N/ha 化肥），以研究地表径流引起的氮损失，并探讨水稻氮代谢对不同氮水平的响应。结果表明，随着氮肥水平的增加，氮通过径流损失和水稻产量同时增加。在水稻生长季节，约 30%的总氮（TN）以铵（NH）的形式流失，而只有 3%以硝酸盐（NO）的形式流失。较高的氮施用量增加了水稻叶片中的碳（C）和氮含量，以及硝酸还原酶（NR）和谷氨酰胺合成酶（GS）的活性，而降低了谷氨酸合酶（GOGAT）和谷氨酸脱氢酶（GDH）的活性。这些结果表明，氮导致了水稻旗叶中同化产物的积累，并刺激了氮代谢过程，同时也刺激了一些保护物质来抵抗低氮胁迫。本研究为改进氮肥管理以减少氮损失和提高水稻产量提供了理论依据。
