Kinzinger Laura, Haberstroh Simon, Mach Judith, Weiler Markus, Orlowski Natalie, Werner Christiane
Ecosystem Physiology, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg im Breisgau, Germany.
Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg im Breisgau, Germany.
Plant Cell Environ. 2025 Oct;48(10):7627-7639. doi: 10.1111/pce.70055. Epub 2025 Jul 10.
Adaptation of root water uptake (RWU) is critical for drought resilience in temperate forest trees, yet information on water sources and uptake depths dynamics is scarce. Continuous in-situ stable isotope measurements in soil and xylem water of Fagus sylvatica during the severe drought 2022 revealed daily changes in RWU depth and water ages. Xylem water comprised mainly recent precipitation in early summer, but winter and spring precipitation contributed up to 70% during drought, with longer transit times (206 ± 60 days) compared to summer precipitation (62 ± 11 days). Concurrently, trees shifted RWU to deeper soil layers while also responding to individual precipitation events by absorbing fresh precipitation from topsoil layers within 2-4 days, demonstrating the significance of individual precipitation events for tree water dynamic. F. sylvatica used > 80% of a fresh precipitation event before drought, but < 20% during recovery, indicating potential drought legacies on precipitation use. Unravelling these rapid dynamics in RWU and water ages offers novel insights into the importance of single and seasonal precipitation events for forest water fluxes.
根系水分吸收（RWU）的适应性对于温带森林树木的抗旱能力至关重要，但关于水源和吸收深度动态的信息却很匮乏。2022年严重干旱期间，对欧洲山毛榉土壤和木质部水分进行的连续原位稳定同位素测量揭示了根系水分吸收深度和水龄的每日变化。木质部水分在初夏主要由近期降水组成，但在干旱期间，冬季和春季降水贡献高达70%，与夏季降水（62±11天）相比，其传输时间更长（206±60天）。与此同时，树木将根系水分吸收转移到更深的土壤层，同时也通过在2 - 4天内从表层土壤吸收新鲜降水来响应个别降水事件，这表明个别降水事件对树木水分动态的重要性。在干旱前，欧洲山毛榉利用了超过80%的一次新鲜降水事件，但在恢复期则不到20%，这表明降水利用可能存在干旱遗留效应。揭示根系水分吸收和水龄的这些快速动态，为单次和季节性降水事件对森林水分通量的重要性提供了新的见解。
