Université de Caen Basse-Normandie, UMR 950 Ecophysiologie Végétale, Agronomie et nutritions N, C, S, Esplanade de la Paix, F-14032 Caen Cedex, France.
J Exp Bot. 2012 Sep;63(14):5245-58. doi: 10.1093/jxb/ers183. Epub 2012 Jul 27.
N-fertilizer use efficiencies are affected by their chemical composition and suffer from potential N-losses by volatilization. In a field lysimeter experiment, (15)N-labelled fertilizers were used to follow N uptake by Brassica napus L. and assess N-losses by volatilization. Use of urea with NBPT (urease inhibitor) showed the best efficiency with the lowest N losses (8% of N applied compared with 25% with urea alone). Plants receiving ammonium sulphate, had similar yield achieved through a better N mobilization from vegetative tissues to the seeds, despite a lower N uptake resulting from a higher volatilization (43% of applied N). Amounts of (15)N in the plant were also higher when plants were fertilized with ammonium nitrate but N-losses reached 23% of applied N. In parallel, hydroponic experiments showed a deleterious effect of ammonium and urea on the growth of oilseed rape. This was alleviated by the nitrate supply, which was preferentially taken up. B. napus was also characterized by a very low potential for urea uptake. BnDUR3 and BnAMT1, encoding urea and ammonium transporters, were up-regulated by urea, suggesting that urea-grown plants suffered from nitrogen deficiency. The results also suggested a role for nitrate as a signal for the expression of BnDUR3, in addition to its role as a major nutrient. Overall, the results of the hydroponic study showed that urea itself does not contribute significantly to the N nutrition of oilseed rape. Moreover, it may contribute indirectly since a better use efficiency for urea fertilizer, which was further increased by the application of a urease inhibitor, was observed in the lysimeter study.
氮肥的利用率受其化学成分的影响，并可能因挥发而导致潜在的氮损失。在田间淋溶实验中，使用（15）N 标记的肥料来跟踪油菜对氮的吸收，并评估挥发导致的氮损失。与单独使用尿素相比，使用带有 NBPT（脲酶抑制剂）的尿素显示出最佳的效率和最低的氮损失（与施入的氮相比，损失 8%）。与单独使用尿素相比，尽管由于挥发较高（施入氮的 43%）导致氮吸收较低，但由于从营养组织向种子更好地动员氮，因此接受硫酸铵的植物的产量相似。当植物用硝酸铵施肥时，植物中（15）N 的含量也更高，但氮损失达到施入氮的 23%。同时，水培实验表明铵态氮和尿素对油菜生长有有害影响。硝酸盐的供应缓解了这种情况，硝酸盐被优先吸收。油菜还表现出对尿素吸收的潜力很低。编码尿素和铵转运蛋白的 BnDUR3 和 BnAMT1 受尿素上调，表明尿素培养的植物遭受氮缺乏。结果还表明，硝酸盐除了作为主要营养物外，还作为信号调节 BnDUR3 的表达。总的来说，水培研究的结果表明，尿素本身对油菜的氮营养没有显著贡献。此外，由于在淋溶实验中观察到尿素肥料的利用率更好，并且通过施用脲酶抑制剂进一步提高，因此尿素可能间接地有助于氮营养。
