Fig. 4. BLR expression pattern. (A,B) Whole mounts showing GUS expression pattern from the BLR::GUS reporter gene. GUS activity is detected in the SAM of the embryo (A) and 8-day-old seedling (B). Weak expression is also in the vasculature of cotyledons and leaves. (C,D) In situ hybridization of wild-type embryos probed with BLR antisense (C), and STM antisense (D). BLR and STM transcripts are detected in the SAM (E,F) In situ hybridization of wild-type inflorescences probed with BLR antisense (E) and STM antisense (F). (G-I) Three consecutive serial sections of an inflorescence apex probed with BLR antisense. BLR is expressed in the SAM, in a pattern similar to that of STM. In initiating floral primordia BLR is first downregulated (arrowheads in G-I) but is subsequently detected in the central region of developing floral primordia and flowers (arrows in E). A low level of BLR expression is also detected at the base of developing flowers, in the pedicel and in the inflorescence stem. Scale bars: 50 µm (A,C-I).