Fig. 5. SCR is induced only in initials by pWER::SHR::GFP. Longitudinal (A-D) and transverse (E,F) confocal images of the same pSCR::YFP_ER, pWER::SHR::GFP transgenic root. In the GFP+YFP mode (see Materials and methods), signals from both GFP and YFP_ER are rendered in green (A,C,E); in the YFP mode, the signal from YFP_ER alone is rendered in yellow (B,D,F). The SCR promoter is active in its normal expression pattern (endodermis, en/co initial and daughter and QC) and in cells in a position that corresponds to the location of the ep/LRC initials (arrowheads) (B,D,F). The SCR promoter is not active in the outermost tissue, even though SHR::GFP is visible in its nuclei (arrow in A,B). QC, quiescent center; st, stele; en, endodermis. Scale bars: 50 µm in A,B; 25 µm in C-F.