Figure 7. Disordered phragmoplast dynamics in cytokinetic root cells of the Arabidopsis pi4kβ1 pi4kβ2 double mutant.

The dynamic transitions of phragmoplast microtubules were recorded by live‐cell time‐lapse imaging.

1. Five‐day‐old seedlings expressing mCherry‐TUA5 were imaged at 1 frame per 2 min. Times are given relative to the instance when the cell plate contacted the peripheral plasma membrane, defined as t0. Cells are outlined by dashed lines in the first and last frames of each series. White arrowhead, ectopic stabilization of microtubules in central phragmoplasts of the pi4kβ1 pi4kβ2 double mutant. Scale bars, 10 μm.
2. Plot profiles obtained from dashed lines marked in (A). Black arrowhead, ectopic stabilization of microtubules in central phragmoplasts of the pi4kβ1 pi4kβ2 double mutant.
3. 3D projections from time points selected from (A), when the transition to a ring phragmoplast has occurred in wild type, but solid phragmoplast persisted in the double mutant. Scale bars, 10 μm.
4. Duration of phragmoplast persistence during cytokinesis, determined from initiation to disbanding. ***, a significant difference (P < 0.001) according to a two‐tailed Mann–Whitney U‐test (wild type, n = 12 cells, 9 roots; pi4kβ1 pi4kβ2, n = 21 cells, 16 roots).