Fig. 1.

DDA1 is expressed in the vasculature and is transcriptionally regulated by auxin and dark exposure. Histochemical GUS analysis of pDDA1:GUS transgenic plants. (A) Seven-day-old seedling. (B) Mature rosette leaf. (C) Root of 7-day-old seedling. (D) Open flower. (E) Silique. (F) Cotyledon of 7-day-old seedling grown under standard conditions. (G) Cotyledon of 7-day-old seedling grown in 10 μM IAA. (H) Seven-day-old seedling grown in constant dark. (I) Root of 7-day-old seedling grown on unsupplemented medium. (J) Seven-day-old seedling root grown on medium supplemented with 85 nM 2,4-D. Size bar in (C) = 50 μm, in (F) = 200 μm, and in (H) and (I) = 100 μm. The magnification in (F) and (G) is the same; the magnification in (I) and (J) is the same.