article published yes Sara Bonetti author Daniel Breitenstein author Simone Fatichi author cf8e546b-a9b0-11f0-a43b-aa89ed1b56d6 Jean‐Christophe Domec author Dani Or author Defining plant hydraulic traits is central to the quantification of ecohydrological processes ranging from land-atmosphere interactions, to tree mortality and water-carbon budgets. A key plant trait is the xylem specific hydraulic conductivity (Kx), that describes the plant's vascular system capacity to transport water. While xylem's vessels and tracheids are dead upon maturity, the xylem is neither inert nor deadwood, various components of the sapwood and surrounding tissue remaining alive and functional. Moreover, the established definition of Kx assumes linear relations between water flux and pressure gradient by tacitly considering the xylem as a “passive conduit”. Here, we re-examine this notion of an inert xylem by systematically characterizing xylem flow in several woody plants using Kx measurements under constant and cyclic pressure gradients. Results show a temporal and pressure gradient dependence of Kx. Additionally, microscopic features in “living branches” are irreversibly modified upon drying of the xylem, thus differentiating the macroscopic definition of Kx for living and dead xylem. The findings highlight the picture of the xylem as a complex and delicate conductive system whose hydraulic behaviour transcends a passive gradient-based flow. The study sheds new light on xylem conceptualization, conductivity measurement protocols, in situ long-distance water transport and ecosystem modelling. Wiley2021 eng Plant hydraulic traitsPlant vascular systemSapflowXylem conductivity measurements 0140-7791 1365-3040 32964494 10.1111/pce.13893 442371-386 yes Bonetti, Sara, et al. “Persistent Decay of Fresh Xylem Hydraulic Conductivity Varies with Pressure Gradient and Marks Plant Responses to Injury.” <i>Plant, Cell &#38; Environment</i>, vol. 44, no. 2, Wiley, 2021, pp. 371–86, doi:<a href="https://doi.org/10.1111/pce.13893">10.1111/pce.13893</a>. S. Bonetti, D. Breitenstein, S. Fatichi, J. Domec, D. Or, Plant, Cell &#38; Environment 44 (2021) 371–386. Bonetti S, Breitenstein D, Fatichi S, Domec J, Or D. Persistent decay of fresh xylem hydraulic conductivity varies with pressure gradient and marks plant responses to injury. <i>Plant, Cell &#38; Environment</i>. 2021;44(2):371-386. doi:<a href="https://doi.org/10.1111/pce.13893">10.1111/pce.13893</a> S. Bonetti, D. Breitenstein, S. Fatichi, J. Domec, and D. Or, “Persistent decay of fresh xylem hydraulic conductivity varies with pressure gradient and marks plant responses to injury,” <i>Plant, Cell &#38; Environment</i>, vol. 44, no. 2. Wiley, pp. 371–386, 2021. Bonetti, Sara, Daniel Breitenstein, Simone Fatichi, Jean‐Christophe Domec, and Dani Or. “Persistent Decay of Fresh Xylem Hydraulic Conductivity Varies with Pressure Gradient and Marks Plant Responses to Injury.” <i>Plant, Cell &#38; Environment</i>. Wiley, 2021. <a href="https://doi.org/10.1111/pce.13893">https://doi.org/10.1111/pce.13893</a>. Bonetti, S., Breitenstein, D., Fatichi, S., Domec, J., &#38; Or, D. (2021). Persistent decay of fresh xylem hydraulic conductivity varies with pressure gradient and marks plant responses to injury. <i>Plant, Cell &#38; Environment</i>. Wiley. <a href="https://doi.org/10.1111/pce.13893">https://doi.org/10.1111/pce.13893</a> Bonetti S, Breitenstein D, Fatichi S, Domec J, Or D. 2021. Persistent decay of fresh xylem hydraulic conductivity varies with pressure gradient and marks plant responses to injury. Plant, Cell &#38; Environment. 44(2), 371–386. 225162026-07-27T12:30:24Z2026-08-07T09:06:00Z