Non-invasive hydrodynamic imaging in plant roots at cellular resolution

A key impediment to studying water-related mechanisms in plants is the inability to non-invasively image water fluxes in cells at high temporal and spatial resolution. Here, we report that Raman microspectroscopy, complemented by hydrodynamic modelling, can achieve this goal - monitoring hydrodynamics within living root tissues at cell- and sub-second-scale resolutions. Raman imaging of water-transporting xylem vessels in Arabidopsis thaliana mutant roots reveals faster xylem water transport in endodermal diffusion barrier mutants. Furthermore, transverse line scans across the root suggest water transported via the root xylem does not re-enter outer root tissues nor the surrounding soil when en-route to shoot tissues if endodermal diffusion barriers are intact, thereby separating 'two water worlds'.

Automated summary

This study used Raman microspectroscopy and hydrodynamic modeling to successfully monitor water dynamics in plant root tissues at high temporal and spatial resolutions. The results revealed faster water transport in xylem vessels of Arabidopsis thaliana mutant roots with endodermal diffusion barrier mutations, and showed that water transported via the root xylem does not re-enter outer root tissues or the surrounding soil if endodermal diffusion barriers are intact, thus separating 'two water worlds'.