@article{6163525072e44807ac3553fdfed8c6a2,
title = "Tracing plant source water dynamics during drought by continuous transpiration measurements: An in-situ stable isotope approach",
abstract = "The isotopic composition of xylem water (δX) is of considerable interest for plant source water studies. In-situ monitored isotopic composition of transpired water (δT) could provide a nondestructive proxy for δX-values. Using flow-through leaf chambers, we monitored 2-hourly δT-dynamics in two tropical plant species, one canopy-forming tree and one understory herbaceous species. In an enclosed rainforest (Biosphere 2), we observed δT-dynamics in response to an experimental severe drought, followed by a 2H deep-water pulse applied belowground before starting regular rain. We also sampled branches to obtain δX-values from cryogenic vacuum extraction (CVE). Daily flux-weighted δ18OT-values were a good proxy for δ18OX-values under well-watered and drought conditions that matched the rainforest's water source. Transpiration-derived δ18OX-values were mostly lower than CVE-derived values. Transpiration-derived δ2HX-values were relatively high compared to source water and consistently higher than CVE-derived values during drought. Tracing the 2H deep-water pulse in real-time showed distinct water uptake and transport responses: a fast and strong contribution of deep water to canopy tree transpiration contrasting with a slow and limited contribution to understory species transpiration. Thus, the in-situ transpiration method is a promising tool to capture rapid dynamics in plant water uptake and use by both woody and nonwoody species.",
keywords = "CRDS, cryogenic vacuum extraction, herbaceous species, laser spectrometry, method comparison, nonwoody, woody, xylem water",
author = "Angelika K{\"u}bert and Maren Dubbert and Ines Bamberger and Kathrin K{\"u}hnhammer and Matthias Beyer and {van Haren}, Joost and Kinzie Bailey and Jia Hu and Meredith, {Laura K.} and {Nemiah Ladd}, S. and Christiane Werner",
note = "Funding Information: We thank all members of the B2WALD team for their valuable support (please see https://arizona.figshare.com/articles/dataset/B2WALD_Campaign_Team_and_Contributions/14632662/2) and special thanks to Jason Deleeuw, Sydney Kerman, Erik Daber and Johannes Ingrisch for support and advice. We also thank two anonymous reviewers for their feedback on this work to improve this manuscript. This work was supported by the European Research Council (ERC consolidator grant #647008 (VOCO2) to C. W.), the Philecology Foundation to Biosphere 2 to L. K. M. and the German Research Foundation (DFG grant #DU1688/1-1 to M. D.). Open Access funding enabled and organized by Projekt DEAL. Funding Information: We thank all members of the B2WALD team for their valuable support (please see https://arizona.figshare.com/articles/dataset/B2WALD_Campaign_Team_and_Contributions/14632662/2 ) and special thanks to Jason Deleeuw, Sydney Kerman, Erik Daber and Johannes Ingrisch for support and advice. We also thank two anonymous reviewers for their feedback on this work to improve this manuscript. This work was supported by the European Research Council (ERC consolidator grant #647008 (VOCO) to C. W.), the Philecology Foundation to Biosphere 2 to L. K. M. and the German Research Foundation (DFG grant #DU1688/1‐1 to M. D.). Open Access funding enabled and organized by Projekt DEAL. 2 Publisher Copyright: {\textcopyright} 2022 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.",
year = "2023",
month = jan,
doi = "10.1111/pce.14475",
language = "English (US)",
volume = "46",
pages = "133--149",
journal = "Plant, Cell and Environment",
issn = "0140-7791",
publisher = "Wiley-Blackwell",
number = "1",
}