Preliminary results of slow flow velocity mapping for analysing flow in plants.

Motivation: Spatially resolved accurate slow-flow measurements in complex plant vasculature are necessary for understanding force and pressure conditions as possible sensory functions in the vascular network. Goal(s): Measuring slow-flow velocities in small-scale phantoms of decreasing inner radii and increasing complexity using microscopic displacement imaging. Approach: Velocities in the xylem sap-flow range, i.e. 1-4 mm/s, are measured with a diffusion weighted RARE sequence using different phantoms mimicking plant vasculature with respective vessel size. Results: The sequence robustness was successfully tested in 190 μm radius tubes with bidirectional flow velocities of 1 mm/s and voxels containing both stationary and flowing water. Impact: Validating the slow flow velocity measurements in phantoms with sub-mm dimensions allows us to confidently apply the Pulsed Field Gradient Turbo Spin-Echo technique for slow-flow measurements with unknown velocities.