Figure 4.
Hydrodynamic prediction and MRV measurements of vacuolar flow. (a) The internodal flow has a helical symmetry: an invariance under a translation along the longitudinal axis combined with a rotation. The two axes that naturally follow from this symmetry are the vector eH, which points along the bands, and the vector eφ , which is orthogonal to the bands. (b) Theoretically predicted flow field along the eH component, showing the vacuolar shear profile. (c) The er and eφ components reveal a small secondary circulation along the centre of the cell. (d) MRI scan of an internode placed in a glass tube, with spiralling lines indicating positions of the neutral line, and coloured bands showing the domains used for velocity measurements. (e) Velocity profiles measured at each of the domains show excellent agreement with the theoretical profile. (Figures modified from [114–116].)