The cortical density of periclinal microtubules does not differ in opposing cells prior to lobe formation. A, Image of periclinal microtubules at the interface of a segment that will form a lobe. B, Processed microtubule image using the cortical occupancy method of Higaki et al. (2010). C, Skeletonized version of the processed image showing segmented microtubules. D, Overlay of the GFP:TUB6 image from B and the microtubule skeleton in C. The ROIs of the future convex (V) and future concave (C) cells are shown at the lobing interface. E, Box plots of the mean cortical occupancy of microtubules in paired convex (V) and concave (C) cells at the lobing interface. ***, Significant difference between the paired cell regions by Student’s t test (P < 0.05).