| 自然丰度法与同位素稀释法测定植物固氮能力的比较 |
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| 作者姓名： | 李润富 牛海山 孔倩 刘强 |
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| 作者单位： | 中国科学院大学资源与环境学院, 北京 101408 |
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| 基金项目： | 中国科学院战略性先导科技专项（XDA20050103）资助 |
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| 摘 要： | 生物固氮是生态系统有效氮的重要来源,目前存在多种测定和计算方法.以青藏高原高寒草原豆科植物团垫黄芪(Astragalus arnoldii)为对象,对比自然丰度法和同位素稀释法的差异,探讨4种计算方法、4种参考植物和2个取样时间对团垫黄芪生物固氮百分率(％Ndfa)评估的影响.结果 表明:参考植物的δ15N在自然生长状...
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| 关 键 词： | 生物固氮 自然丰度法 同位素稀释法 青藏高原 高寒草原 15N |
| 收稿时间： | 2020-10-26 |
| 修稿时间： | 2021-01-28 |
Comparison of natural 15N abundance technique and 15N dilution technique in the determination of plant nitrogen fixation |
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| Authors: | LI Runfu NIU Haishan KONG Qian LIU Qiang |
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| Institution: | College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China |
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| Abstract: | Biological nitrogen fixation (BNF) is an important source of nitrogen in ecosystem, therefore, several experimental techniques and calculating methods have been developed to quantify the contribution of BNF to plants and vegetations. In this study, percentage of plant N derived from N2-fixation (%Ndfa) was evaluated for a leguminous species, Astragalus arnoldii, in an alpine steppe in Qinghai-Tibet Plateau in order to compare two dominant in situ experimental techniques with different calculating approaches, reference plants, and sampling times. The δ15N values of four reference plants, i.e., Stipa purpurea, Kobresia pygmaea, Leontopodium nanum, and Carex moorcroftii, were significantly lower in late August than in late July (P<0.05). However, they were significantly higher in later August, 30 days after application of (15NH4)2SO4 to soil, than late July which was 24h after labeling (P<0.05). In either site with or without (15NH4)2SO4 application, δ15N of A. arnoldii did not differ in the two sampling times. Besides,%Ndfa of A. arnoldii did not differ between calculation based on 15N excess relative to atmospheric N2 and that relative to unlabeled plants. Nevertheless,%Ndfa measured by natural abundance technique was significantly higher than that by isotope dilution technique (P<0.05) except for L. nanum as the reference species. The sampling time had a significant effect on estimated%Ndfa values in both the naturalabundance technique (F=89.906, P<0.01), and isotope dilution technique (F=496.712, P<0.01). |
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| Keywords: | biological nitrogen fixation natural abundance technique isotope dilution technique Qinghai-Tibet plateau alpine steppe 15N |
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