PPB and phragmoplast angle measurements, micrographs, and time-lapse imaging of dividing cells expressing CFP-TUBULIN. A, PPB and phragmoplast angle orientation in dividing root cells. The angle was measured between the long axis of the cell wall and the orientation of the PPB or phragmoplast. The 80° and 100° angles are indicated by dotted lines. A line heterozygous for air9 and tan1 in the Ler background was used for Ler. Asterisks indicate statistically significant differences in distributions (F test, P < 0.0001). B and C, Merged confocal images showing CFP-TUBULIN (green) and propidium iodide (magenta) of tan1 air9 double mutant root cells. Images show PPBs (B) and phragmoplasts (C) with angles outside the 80° to 100° range. D to K, Time-lapse images of tan1 (D), air9 (F), oriented tan1 air9 (H), and misoriented tan1 air9 (J) division, showing the different phases of mitosis. Merged images of completed division starting with a PPB (green) and ending with a new cell wall (magenta) are shown for tan1 (E), air9 (G), properly oriented tan1 air9 division (I), and misoriented cell wall in a tan1 air9 division (K). Minutes and seconds are given in white at the bottom left sides of the time-lapse images. Bars = 5 µm.