Root cortical cells in exocyst mutants elongate at a slower rate in shorter elongation zones. (A) Composite confocal image of a Col-0 root (bar = 100 microns). (B-G) Cortical cells in elongation zones, highlighted in white (bar = 50 μM). Col-0 (A, B,); exo70A1 (C); sec5a exo70A1 (D); sec8-4 exo70A1 (E); sec8-3 (F); exo84b-1 (G). (H) Exponential curves fitted to cell length data for elongation zones of 14 cell files (7 roots) of each genotype. The curves allow estimation of relative elongation rates for each genotype (Figure 2H) (I) Reduced cell elongation rates are not evident in the meristematic zones of exocyst mutants or Col-0 treated with 10 μM BFA compared to Col-0; error bars represent standard error with n = 7 roots per genotype. (see Additional file 2).