Functional status of xylem through time

Authors: BRODERSEN, CRAIG - Yale University; RODDY, ADAM - Yale University; WASON, JAY - University Of Maine; McElrone, Andrew

Submitted to: Annual Reviews of Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2019
Publication Date: 4/1/2019
Citation: Brodersen, C., Roddy, A., Wason, J., McElrone, A.J. 2019. Functional status of xylem through time. Annual Reviews of Plant Biology. 70:407-433. https://doi.org/10.1146/annurev-arplant-050718-100455.
DOI: https://doi.org/10.1146/annurev-arplant-050718-100455

Interpretive Summary: Water transport in vascular plants represents a critical component of terrestrial water cycles, and supplies the water needed in leaves for the exchange of CO2 in the atmosphere for photosynthesis. Yet, many of the fundamental principles of water transport are difficult to assess given the scale and location of plant xylem, and the negative pressure environment that provides the driving force for long distance transport. Here we review the mechanistic principles that underpin long distance water transport in vascular plants, with a focus on woody species. We also discuss the recent development of non-invasive tools to study the functional status of xylem networks in planta. Limitations of current methods to detect and quantify cavitation, sap flow, and the coordination of hydraulic dysfunction with other physiological processes are assessed. Future avenues of research focused on cross-validation of plant hydraulics methods are discussed, as well as a proposed fundamental shift in the methodology and theory used to characterize and measure plant water use.

Technical Abstract: Water transport in vascular plants represents a critical component of terrestrial water cycles, and supplies the water needed in leaves for the exchange of CO2 in the atmosphere for photosynthesis. Yet, many of the fundamental principles of water transport are difficult to assess given the scale and location of plant xylem, and the negative pressure environment that provides the driving force for long distance transport. Here we review the mechanistic principles that underpin long distance water transport in vascular plants, with a focus on woody species. We also discuss the recent development of non-invasive tools to study the functional status of xylem networks in planta. Limitations of current methods to detect and quantify cavitation, sap flow, and the coordination of hydraulic dysfunction with other physiological processes are assessed. Future avenues of research focused on cross-validation of plant hydraulics methods are discussed, as well as a proposed fundamental shift in the methodology and theory used to characterize and measure plant water use.