MRI for soil and plant research

Magnetic resonance imaging uses the nuclear magnetic resonance effect (NMR) for non-invasive, 3D high resolution imaging. Many atomic nuclei such as 1H, 23Na, 19F, which have a microscopic magnetic moment proportional to their spin, show this effect. They interact with an external magnetic field, in which they can be excited, they subse­quent­ly relax, and send a signal. This signal con­tains information about the content of the respec­tive nucleus, e.g. 1H2O, but also about its physical and chemical environment. After analysis of the measurements, MRI maps water or NaCl contents, but also relaxation times which allow for conclusions on the properties of the porous medium. Spatial reso­lu­tions of 0.2 mm are routinely achievable.

In soil and plant research, we use MRI for imaging the development of root systems (Fig. 2), and their correlation with water of salt content. Furthermore, water flow and uptake pathways are visible by application of MRI sensitive tracer substances. An example is given in Fig. 3, where GdDTA tracer is enriched in certain zones around roots.

Fig. 3: GdDTPA enrichment during continuous irrigation of a lupin plant. a) root system and selected axial slices. b) enrichment pattern develop­ment during several days. Resolution is 0.23 mm x 0.23 mm, slice thick­ness 2 mm.
From Haber-Pohlmeier et al., Water Resour. Res. 53, 7469–7480, (2017) doi:10.1002/2017WR020832.

Last Modified: 25.05.2022