T16H activity and CYP71D351 (T16H2) transcripts are specifically located in epidermis of C. roseus leaves. A and B, Analysis of T16H enzymatic activity (A) and relative expression of CYP71D351 in leaf epidermis-enriched protein/transcript extracts produced by carborundum abrasion compared with that found in whole leaves (B). Cr60S was used as a reference gene. Ep, Epidermis; WL, whole leaf. C to F, Analysis of CYP71D351 and CYP71D12 transcript distribution performed by RNA in situ hybridization. Serial sections of young developing leaves were hybridized either with CYP71D12 antisense (AS) probes (C), CYP71D351 antisense probes (E), CYP71D12 sense (S) probes (D), or CYP71D351 sense probes (F) used as negative controls. ab, Abaxial epidermis; ad, adaxial epidermis. Bars = 100 µm.