Magnetic Resonance Imaging Techniques for Visualization of Root Growth and Root Water Uptake Processes

Abstract

Root growth and water uptake processes in the subsurface are hard to observe due to the opaque nature of soil. Classical methods are either invasive or restricted to model setups like two-dimensional rhizoboxes and transparent media. Therefore, during the past two decades, noninvasive methods for monitoring root-soil processes have become popular. Among these, magnetic resonance imaging (MRI)is the most versatile one. It allows one to visualize root features like anatomy and root system architecture, water content distribution in the surrounding soil, and tracer movements in soil and roots. In this chapter, the principles of MRI are introduced first, followed by a short description of necessary hardware components. The third section reviews investigations of root systems and water uptake patterns in soils using MRI and discusses the effect of experimental parameters. In the fourth section, the usage of contrast agents for the investigation of root water processes is demonstrated. This also includes our recent results on the visualization of the transport processes in root soil systems using GdDTPA as MRI contrast agent.