This Thesis treats one of the new techniques in plant science i.e. nuclear magnetic resonance imaging (NMRi) applied to water motion in plants. It is a challenge to measure this motion in intact plants quantitatively, because plants impose specific problems when studied using NMRi. At high magnetic field strength air-filled intercellular spaces in the plant tissue cause susceptibility-related local magnetic field inhomogeneities, which are much smaller at low magnetic field strength. The inherently low signal-to-noise ratio at low magnetic fields is compensated by the possibility to record a long train of spin-echoes, since generally the spin-spin relaxation time T2 at low magnetic field is longer than at high magnetic field.