Use of magnetic resonance imaging in the study of plants and soils
The nondestructive study of plants and soils in situ has historically been difficult due to the inherently opaque nature of the system. Repeated study of root growth and physiological processes in bulk soil has been impossible without techniques for remote sensing, such as x-ray, computed tomography, rhizotrons, or magnetic resonance imaging (MRI). Magnetic resonance imaging techniques are now providing tools for the direct, nondestructive study of plants and soils. New smaller bore, high field MRI scanners can provide resolutions (10-100 μm) far superior to resolutions provided by clinical scanners (>1 mm), and can truly be considered magnetic resonance microscopy (MRM). Images can be repeatedly acquired over time, providing both spatial and temporal information. The technique has provided information on water extraction by roots, root growth and function, flow of water through porous media, water distribution, and binding patterns in sand-sandstone and in planta, and plant physiological processes. The chemical environment can also be probed by examinations of relaxation times and diffusion coefficients measured by MRI. As the technique is further developed, many new and unique applications will be found.
