<sup>1</sup>H and <sup>31</sup>P NMR investigation of gadolinium uptake in maize roots
Quiquampoix H., Ratcliffe RG., Ratković S., Ratković S., Vučinić Z.
Low-resolution 1 H NMR and high-resolution 31 P NMR were used to study the absorption of gadolinium (Gd) by the root tissues of maize seedlings. Gd was supplied as either Gd 3+ or Gd(DTPA) 2- , and its presence in the tissue caused changes in the relaxation properties of the tissue water and of various phosphorylated metabolites. 1 H NMR relaxation measurements indicated that soluble Gd accumulated in the tissue more rapidly with Gd(DTPA) 2- than with Gd 3+ , and this was attributed to the precipitation of Gd 3+ in the root. Electron microscopy and x-ray microanalysis confirmed the presence of deposits containing Gd and phosphorus (P) in the extracellular space of the tissue. 31 P NMR showed the presence of soluble Gd in both the cytoplasm and the vacuole of roots treated with Gd 3+ and, thus, proved that Gd 3+ can reach the symplast, contrary to the usual assumption about the lanthanides. Evidence for the immobilization of P by Gd 3+ and for the vacuolar breakdown of Gd(DTPA) 2- was also obtained from the 31 P NMR spectra. © 1990.