Retrieving nitrogen isotopic signatures from fresh leaf reflectance spectra: disentangling δ(15)N from biochemical and structural leaf properties.
Retrieving nitrogen isotopic signatures from fresh leaf reflectance spectra: disentangling δ(15)N from biochemical and structural leaf properties.
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DOI：
10.3389/fpls.2015.00307
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发表时间：
2015
影响因子：
5.6
通讯作者：
Werner C
中科院分区：
文献类型：
--
作者：
Hellmann C;Große-Stoltenberg A;Lauströ V;Oldeland J;Werner C
将遥感方法与稳定同位素生态学联系起来，为研究从小到大空间尺度的生态过程提供了一种有前景的方法。在这里，我们表明，可以沿着固定 N2 入侵物种的氮输入增加的空间梯度，在田间样品的新鲜叶子反射光谱中检测到 δ15N。然而，在现场数据中，尚不清楚 δ15N 是否直接影响叶片反射光谱，或者这种关系是否基于 δ15N 与叶面氮含量或其他叶片特性之间的协变。使用 15N 标记方法，我们在不同叶子发育和生理状态的三种植物物种中独立于任何其他叶子特性进行了实验性改变 δ15N。使用叶片反射光谱作为预测变量，可以通过偏最小二乘 (PLS) 回归成功地对 δ15N 进行建模。 PLS 模型解释了物种内 δ15N 变化的 53-73%。对于预测 δ15N 很重要的几个波长区域在不同物种之间是一致的，并且可能还与含氮分子键的已知吸收特征有关。通过消除与其他叶子特性的协变来解释反射率和 δ15N 之间的关系，我们的结果表明 15N 本身对叶子反射光谱具有固有的影响。因此，我们的研究证实了使用光谱测量来检索生态研究的同位素特征，并鼓励未来的发展。此外，我们的结果凸显了光学测量将同位素生态学扩展到更大空间尺度的巨大潜力。
Linking remote sensing methodology to stable isotope ecology provides a promising approach to study ecological processes from small to large spatial scales. Here, we show that δ15N can be detected in fresh leaf reflectance spectra of field samples along a spatial gradient of increasing nitrogen input from an N2-fixing invasive species. However, in field data it is unclear whether δ15N directly influences leaf reflectance spectra or if the relationship is based on covariation between δ15N and foliar nitrogen content or other leaf properties. Using a 15N-labeling approach, we experimentally varied δ15N independently of any other leaf properties in three plant species across different leaf developmental and physiological states. δ15N could successfully be modeled by means of partial least squares (PLSs) regressions, using leaf reflectance spectra as predictor variables. PLS models explained 53–73% of the variation in δ15N within species. Several wavelength regions important for predicting δ15N were consistent across species and could furthermore be related to known absorption features of N-containing molecular bonds. By eliminating covariation with other leaf properties as an explanation for the relationship between reflectance and δ15N, our results demonstrate that 15N itself has an inherent effect on leaf reflectance spectra. Thus, our study substantiates the use of spectroscopic measurements to retrieve isotopic signatures for ecological studies and encourages future development. Furthermore, our results highlight the great potential of optical measurements for up-scaling isotope ecology to larger spatial scales.
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DOI：
10.1109/tgrs.2011.2104964
发表时间：
2011-07-01
影响因子：
8.2
作者：
Elmore, Andrew J.;Craine, Joseph M.
通讯作者：
Craine, Joseph M.
影响因子：
13.5
作者：
Fourty, T;Baret, F;Verdebout, J
通讯作者：
Verdebout, J
影响因子：
3.9
作者：
Beyschlag, W.;Hanisch, S.;Werner, C.
通讯作者：
Werner, C.
影响因子：
13.5
作者：
Bousquet, L;Lachérade, S;Moya, I
通讯作者：
Moya, I
影响因子：
4.6
作者：
Beever, EA;Swihart, RK;Bestelmeyer, BT
通讯作者：
Bestelmeyer, BT