Quantification of water transport in plants with NMR imaging.
A new nuclear magnetic resonance imaging (NMRi) method is described to calculate the characteristics of water transport in plant stems. Here, dynamic NMRi is used as a non-invasive technique to record the distribution of displacements of protons for each pixel in the NMR image. Using the NMR-signal of the stationary water in a reference tube for calibration, the following characteristics can be calculated per pixel without advance knowledge of the flow-profile in that pixel: the amount of stationary water, the amount of flowing water, the cross-sectional area of flow, the average linear flow velocity of the flowing water, and the volume flow. The accuracy of the method is demonstrated with a stem segment of a chrysanthemum flower by comparing the volume flow, measured with NMR, with the actual volumetric uptake, measured with a balance. NMR measurements corresponded to the balance uptake measurements with a rms error of 0.11 mg s(-1) in a range of 0 to 1.8 mg s(-1). Local changes in flow characteristics of individual voxels of a sample (e.g. intact plant) can be studied as a function of time and of any conceivable changes the sample experiences on a time-scale, longer than the measurement time of a complete set of pixel-propagators (17 min).
Scheenen
T W
TW
Department of Biomolecular Sciences, Laboratory of Molecular Physics, Wageningen University, Dreijenlaan 3, 6703 HA, Wageningen, The Netherlands.
van Dusschoten
D
D
de Jager
P A
PA
Van As
H
H
D009682:Magnetic Resonance Spectroscopy; D018547:Plant Stems / Q000378:metabolism*; D011522:Protons; D014867:Water / Q000378:metabolism*
D011522:Protons; D014867:Water