EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Plants maximize the conductive efficiency of the xylem 

Oskar Franklin1,2, Peter Fransson2, Florian Hofhansl1, and Jaideep Joshi1
Oskar Franklin et al.
  • 1International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria
  • 2Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden

In vast areas of the world, the growth of forests and vegetation is water-limited and plant survival depends on the ability to avoid catastrophic hydraulic failure. Therefore, it is surprising that plants take high hydraulic risks by operating at water potentials (ψ) that induce partial failure of the water conduits (xylem) 1, and which makes them susceptible to drought mortality under climate change 2. Here we present an eco-evolutionary optimality principle for xylem design that explains this phenomenon - xylem is adapted to maximize its effective conductivity. A simple relationship emerges between the xylem intrinsic tolerance to high negative water potential (ψ50) and the environmentally dependent minimum ψ, which explains observed patterns across and within species. The theory provides a fundamental conduit-level principle that complements previously described principles at higher organizational levels, such as hydraulic-network scaling and drought-avoidance behavior. The new optimality principle may be universally valid, from within-individuals to across-species, and thus improve our basic understanding of drought tolerance of plants and forests globally.   

How to cite: Franklin, O., Fransson, P., Hofhansl, F., and Joshi, J.: Plants maximize the conductive efficiency of the xylem , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9863,, 2022.