Subcellular and tissue localization of ZmNRAMP2 in maize. A–D, Tonoplast localization of ZmNRAMP2 in maize mesophyll protoplasts. Maize mesophyll protoplasts transiently expressing ZmNRAMP2–eGFP fusion protein were imaged by confocal laser microscopy. A, GFP fluorescence of ZmNRAMP2–eGFP, (B) chlorophyll autofluorescence, (C) bright-field, (D) merged images. Nu, nuclear; Ch, chloroplast. Scale bars = 5 μm. E–H, In situ RNA hybridization in maize roots with the ZmNRAMP2 antisense probe. E, Red fluorescence revealed by antisense probe of ZmNRAMP2, (F) root structure dyed by DAPI, (G) merged images, (H) enlargement of the yellow dotted box in (G). Ep, epidermis; co, cortex; en, endodermis; pe, pericycle; st, stele; xy, xylem; xp, xylem parenchyma cells; ph, phloem; Scale bars = 40 μm.