| 景建元,孙晓,杨阳,李娜,田肖肖,吕慎强,王林权.施氮水平对冬小麦冠层氨挥发的影响[J].农业环境科学学报,2017,36(2):401-408. |
| 施氮水平对冬小麦冠层氨挥发的影响 |
| Ammonia volatilization of winter wheat canopy under different nitrogen rates |
| 投稿时间：2016-09-23 |
| DOI：10.11654/jaes.2016-1233 |
| 中文关键词: 冠层氨挥发 冬小麦 质外体NH4+浓度 氨气补偿点 谷氨酰胺合成酶（GS） |
| 英文关键词: canopy ammonia volatilization winter wheat apoplastic NH4+ concentration ammonia compensation point glutamine synthetase(GS) |
| 基金项目:国家公益性行业（农业）科研专项（201503124） |
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| 摘要点击次数: 1979 |
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| 中文摘要: |
| 为探索冬小麦全生育期冠层氨挥发规律、主要影响因素及其对麦田氨挥发的贡献率，设置0、90、180 kg N·hm-2三种氮素水平，利用改进型通气式氨气捕获装置，原位分析冬小麦冠层氨挥发速率及其与叶片氮素生理指标的关系。结果表明：麦田氨挥发主要发生在施肥后2~3周，全生育期累积挥发量为3.773~8.704 kg N·hm-2，施氮显著提高了麦田氨挥发累积量（P<0.05），土壤与冠层氨挥发累积量分别为3.289~7.773 kg N·hm-2和0.750~1.461 kg N·hm-2，对麦田氨挥发的贡献率分别为87.2%~89.3%和15.4%~19.9%。不施氮条件下，冠层无氨气吸收；低施氮（90 kg N·hm-2）下，冠层氨气吸收主要发生在苗期；高施氮（180 kg N·hm-2）下，苗期、返青期和灌浆前期冠层均有氨气吸收发生。冠层氨挥发主要发生在开花期、灌浆末期至枯死期，分别占冠层氨挥发的4.5%~9.3%和79.1%~99.0%；冠层氨挥发速率与叶片氨气补偿点、质外体NH4+浓度显著正相关（P<0.05），与谷氨酰胺合成酶（GS）活性、质外体溶液pH相关关系不显著（P>0.05）。总之，开花前，不施肥条件下冬小麦冠层向大气中释放氨，施肥后，冠层从大气中吸收氨。冬小麦开花后，不论施肥与否，冠层都向大气层释放氨。 |
| 英文摘要: |
| A single factor field experiment with three nitrogen rates(0, 90, and 180 kg N·hm-2) was conducted in winter wheat during the 2015-2016 growth season. Ammonia volatilization from both soil and canopy in winter wheat field were measured with the modified vented ammonia trap chambers. Glutamine synthetase(GS) activity in leaves, apoplastic NH4+ concentration and pH, and ammonia compensation point were determined simultaneously. Obtained results showed that field ammonia volatilization mainly occurred within the 2~3 weeks after N fertilization. In the whole growing season, ammonia volatilization totaled in 3.773~8.704 kg N·hm-2, and it increased significantly with the increase of N fertilization rates, of which 3.289~7.773 kg N·hm-2 were from soil, accounting for 87.2%~89.3% of the total; and 0.750~1.461 kg N·hm-2 from the canopy, accounting for 15.4%~19.9% of the total. It was found that the canopy absorbed volatilized ammonia during seedling stage under lower nitrogen application rate(90 kg N·hm-2), and during seedling, returning green and early grain filling stage under higher N application rate(180 kg N·hm-2), but did not under no N fertilization. The net canopy ammonia volatilization mainly occurred at flowering and late grain filling stage, accounting for 4.5%~9.3% and 79.1%~99.0% of total canopy ammonia volatilization during the whole growing season, respectively. Canopy ammonia fluxes were positively correlated with the ammonia compensation point and apoplastic NH4+ concentration, but showed no relation to the GS activity in leaves and apoplastic pH. In summary, winter wheat canopy volatilizes ammonia to the atmosphere past flowering no matter fertilization or not, but it absorbs ammonia from the atmosphere with N fertilization, and emits ammonia without N fertilization during the vegetative stages. |
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