Magnetic susceptibility shift selected imaging (MESSI) and localized ¹H₂O spectroscopy in living plant tissues

Maize root segments permeated with aqueous solutions of the paramagnetic agents GdDTPA^2- or DyDTPA-BMA display two well-resolved NMR peaks corresponding to the signals from intracellular and extracellular ¹H₂O, which arise from well-understood bulk magnetic susceptibility effects. This allows each component to be studied separately. Images obtained at each frequency with MESSI editing, and single- and multiple-voxel ('spectroscopic imaging') localized spectra, clearly indicate that the agents permeate into the interstitial spaces, and into the longitudinal (xylem/phloem) channels in the stele (core) of the root, confirming earlier assessments. We believe these are the first images of a multicellular tissue acquired in vivo exclusively from the intracellular water proton resonance. This method can be further exploited to study water transport in similar systems. Copyright (C) 2000 John Wiley and Sons, Ltd.