Studies of plants in modern catchment systems can serve to improve the level of understanding of sedimentary plant wax hydrogen isotope (δ²H) data by directly investigating the link between local climate conditions, plant source water, leaf water, and plant lipids for individual plant species. Here we present such an application to compare two lake catchments with different basin morphologies in Estonia. We sampled leaf and xylem water, as well as leaf waxes from the seven common plant species in each catchment, and soil water. We then measured the δ²H values of all waters, and of n-alkanes (δ²H_n–alk) from the plant waxes, as well as surface lake sediments. We applied a Péclet modified Craig-Gordon leaf water model using local precipitation isotope and climate data to characterize the δ²H values of the biosynthetic source water pool throughout the entire growth season. The data and model results provide a detailed view of how the input hydro-climatic signals from the precipitation δ²H values were modified by environmental and plant physiological conditions and ultimately by the biosynthetic isotope fractionation associated with n–alkane production by each plant species. We report both average apparent (ε_app = –92 ± 21 ‰) and biosynthetic (ε_bio = –132 ± 19 ‰) hydrogen isotope fractionation factors of all species from the studied catchments. This information serves as a foundation for sedimentary organic geochemistry and paleoclimate studies, which allows for more direct and quantitative links to be made between sedimentary plant wax δ²H values and the climate signal contained in plant source water.

对现代流域系统中植物的研究可以通过直接调查当地气候条件、植物源水、叶水和单个植物的植物脂质之间的联系来提高对沉积植物蜡氢同位素 (δ ² H) 数据的理解水平物种。在这里，我们提出了这样一个应用程序来比较爱沙尼亚具有不同盆地形态的两个湖泊流域。我们对每个流域七种常见植物的叶子和木质部水以及叶蜡和土壤水进行了采样。然后我们测量了所有水和正构烷烃的δ ² H 值(δ ² H _n–alk）来自植物蜡以及表层湖泊沉积物。我们应用 Péclet 修正的 Craig-Gordon 叶水模型，利用当地降水同位素和气候数据来表征整个生长季节生物合成源水池的δ ^{2 H 值。数据和模型结果提供了关于来自降水 δ 2} H 值的输入水文气候信号如何通过环境和植物生理条件以及最终通过与每个植物物种的正烷烃生产相关的生物合成同位素分馏进行修改的详细视图。我们报告了平均表观 (ε _app  = –92 ± 21 ‰) 和生物合成 (ε _bio = –132 ± 19 ‰) 所研究流域所有物种的氢同位素分馏因子。^{这些信息可作为沉积有机地球化学和古气候研究的基础，从而可以在沉积植物蜡δ 2} H值与植物源水中包含的气候信号之间建立更直接和定量的联系。