Histochemical analysis of GUS reporter gene expression from the ESK1 promoter.

A. Expression in whole plantlets 4 days after germination (A1, A2) and 10 days after germination (A3, A4, A5) with magnification of root (A4) and leaf (A5). B. Transverse section of hypocotyls, before (B1, B2) and after floral transition (B3, B4). C. Transverse section of stem (C1, C2). Double-headed arrow indicates the position of cross-section in B2. Red arrowheads indicate interfascicular fibers (B3) or sclerenchyma (C1, C2) and black arrowheads indicate newly-formed xylem cell (B1, B2, B4, C1, C2). X, xylem; P, phloem.