RER gene expression and RER3 protein localization. A to O, Expression of RE, RER1, and RER3 in leaves. GUS activity of RE_pro:GUS (A–E), RER1_pro:GUS (F–J), and RER3_pro:GUS (K–O) transgenic plants in the Col-0 background. Magnifications are shown for the spongy mesophyll (D, I, and N) and lateral hydathodes (E, J, and O). bsc, Bundle sheath cells. P to U, Expression of the RER3:GFP fusion protein. Detail of an epidermal cell from the hypocotyl (P–R), the root epidermis at the differentiation region (S), and cleared palisade mesophyll cells (T and U). Red channel: chlorophyll autofluorescence (R) or propidium iodide staining (S) of cell walls. ip, Immature plastids. Pictures were taken on samples harvested 11 das. Bars = 0.5 mm (A–C, F–H, and K–M), 40 µm (D, E, I, J, N, and O), and 20 µm (P–U).