Immunolocalization of CBP70 in longitudinal sections of the root tip and on cross-sections of the mesocotyl of etiolated maize seedlings. LR White-embedded sections of the root tip (A–C) and mesocotyl (D, E) of dark-grown 4-d-old maize seedlings were analysed. (A, C, D, E) Sections were incubated with mouse anti-CBP70 mAb of the second group (523), biotinylated anti-mouse antibody, and streptavidin-alkaline phosphatase conjugate. (B) A negative control: sections incubated with non-immune serum were not stained. (A–C) Sections were post-stained with safranin. (A) CBP70 was detected in amyloplasts of the columella of the root cap (black arrow). Broken line designates a boundary between the root apex and root cap. Dotted lines enclose the zones of columella (CL) and calyptrogen (CP). Amyloplasts with stained CBP70 are well distinguished in the columella cells (black arrow). (C) A 2.5-fold magnified view of (A). (D) CBP70 was detected in plastids of parenchymal cells surrounding vascular bundles (black arrow). (E) No CBP70 was detected in the mesocotyl large parenchymal and epidermal cells. Scale bars are 75 μm (A), 60 μm (B, D), 40 μm (E), and 30 μm (C).