title: Functional water flow pathways and hydraulic regulation in the xylem network of Arabidopsis.
abstract: In vascular plants, the xylem network constitutes a complex microfluidic system. The relationship between vascular network architecture and functional hydraulic regulation during actual water flow remains unexplored. Here, we developed a method to visualize individual xylem vessels of the 3D xylem network of Arabidopsis thaliana, and to analyze the functional activities of these vessels using synchrotron X-ray computed tomography with hydrophilic gold nanoparticles as flow tracers. We show how the organization of the xylem network changes dynamically throughout the plant, and reveal how the elementary units of this transport system are organized to ensure both long-distance axial water transport and local lateral water transport. Xylem vessels form distinct clusters that operate as functional units, and the activity of these units, which determines water flow pathways, is modulated not only by varying the number and size of xylem vessels, but also by altering their interconnectivity and spatial arrangement. Based on these findings, we propose a regulatory model of water transport that ensures hydraulic efficiency and safety.
authors.affiliation: Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea These authors contributed equally to this work.
authors.forename: Joonghyuk
authors.initials: J
authors.lastname: Park
authors.affiliation: Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea These authors contributed equally to this work. Present address: Global Conservation Agriculture Program, International Maize and Wheat Improvement Center (CIMMYT), P.O. Box 5689, Addis Ababa, Ethiopia.
authors.forename: Hae Koo
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Jeongeun
authors.initials: J
authors.lastname: Ryu
authors.affiliation: Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Sungsook
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea sjlee@postech.ac.kr ihwang@postech.ac.kr.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea sjlee@postech.ac.kr ihwang@postech.ac.kr.
authors.forename: Ildoo
authors.initials: I
authors.lastname: Hwang
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000378:metabolism* / Q000648:ultrastructure; D001692:Biological Transport; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D008954:Models, Biological; D017356:Synchrotrons; D014057:Tomography, X-Ray Computed; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D014867:Water; D006046:Gold
keywords: Arabidopsis thaliana; Gold nanoparticle; Hydraulic regulation; Synchrotron X-ray CT; Water transport; Xylem network