Plant δ15N Correlates with the Transpiration Efficiency of Nitrogen Acquisition in Tropical Trees
Plant δ15N Correlates with the Transpiration Efficiency of Nitrogen Acquisition in Tropical Trees
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DOI：
10.1104/pp.109.145870
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发表时间：
2009-11-01
期刊：
影响因子：
7.4
通讯作者：
Turner, Benjamin L.
中科院分区：
文献类型：
--
作者：
Cernusak, Lucas A.;Winter, Klaus;Turner, Benjamin L.
基于对土壤中稳态硝酸盐吸收过程中N-15/N-14分馏理论模型的考虑，我们假设，对于生长在普通土壤环境中的植物，全植物Δ N-15（Δ（P））应该作为氮获取的蒸腾效率（F-N/nu）以及Δ（P）和根Δ N-15之间的差（Δ（P）-Δ（R））的函数而变化。我们测试了这些假设与几个热带树木和藤本植物的测量。与理论预期一致，F-N/v和delta（P）- delta（R）都是delta（P）变化的重要来源，并且delta（P）与F-N/v之间的关系在非固氮和固氮物种之间不同。我们解释了δ（P）和F-N/nu之间的相关性，这是由于根细胞质膜上无机氮流出与流入比率的变化造成的。这些结果提供了一个简单的解释，在三角洲N-15陆生植物的变化，并了解生态系统中的氮循环的影响。
Based upon considerations of a theoretical model of N-15/N-14 fractionation during steady-state nitrate uptake from soil, we hypothesized that, for plants grown in a common soil environment, whole-plant delta N-15 (delta(P)) should vary as a function of the transpiration efficiency of nitrogen acquisition (F-N/nu) and the difference between delta(P) and root delta N-15 (delta(P) - delta(R)). We tested these hypotheses with measurements of several tropical tree and liana species. Consistent with theoretical expectations, both F-N/v and delta(P) - delta(R) were significant sources of variation in delta(P), and the relationship between delta(P) and F-N/v differed between non-N-2-fixing and N-2-fixing species. We interpret the correlation between delta(P) and F-N/nu as resulting from variation in mineral nitrogen efflux-to-influx ratios across plasma membranes of root cells. These results provide a simple explanation of variation in delta N-15 of terrestrial plants and have implications for understanding nitrogen cycling in ecosystems.