Figure 4.

F-actin organization in living wild-type, agd1-1, and ark1-4 roots as revealed by the GFP-ABD2-GFP reporter. A, Straight-growing wild-type root hairs show longitudinal actin cables (arrowheads) and diffuse fluorescence at the apical 10 to 20 μm (arrows). B, A wavy root hair of agd1-1 shows diffuse labeling at the tip (arrowhead) and thick longitudinal bundles along the center of the cell (arrow). C, A root hair of agd1-1 showing extreme spiral growth. In this root hair, distinct F-actin bundles follow the outline of the cell (arrowheads) and extend to the very tip of the root hair (arrow). D, A root hair of agd1-1 showing extreme wavy growth. In this cell, longitudinal F-actin bundles extend very close to the tip (arrow). E, A wavy and swollen root hair of ark1-4 showing F-actin bundles at the extreme tip (arrow). F, A root hair of ark1-4 with three tips also exhibits distinct F-actin bundles that entirely occupy the tip regions of the cell (arrows). Images are projections of 30 to 40 optical sections taken at 0.5-μm intervals. Bars = 20 μm.