pDR5:VENUS patterns and cell morphology in wild‐type (WT) and PDR1 OE Petunia hybrida root tips. (a, b) pDR5:VENUS in 14‐d‐old WT (a) and PDR1 OE root (b). (c) Pattern of pDR5:VENUS in WT (left) and PDR1 OE root tip (right). (d) Digital quantification of pDR5:VENUS fluorescence in WT and PDR1 OE epidermal/cortex cells (epi/cortex) and central root vasculature (vasculature). (e) Representative propidium iodide‐stained root tips. The asterisk is located at the border between the division and the elongation zone (EZ). (f) Quantification of the cell length of the first five cells in the root tip EZ. Bars: 200 μm (a, b); 40 μm (c, e). Values are means ± SE. *, P < 0.05; ***, P < 0.0005.