Figure 6.

CST is expressed in floral organ AZs and other specific tissues. A, A translational fusion of the CST regulatory region to the GUS reporter was created. B, Expression of GUS is first detected in stage 15 flowers prior to organ shedding (stage 16) and diminishes by mid stage 17. Flowers at consecutive positions along the inflorescence are shown, with the floral stages indicated below. C and D, During and after organ abscission, a dynamic pattern of GUS expression is seen in epidermal AZ cells. The early patches of GUS expression in subepidermal cells of the floral pedicel (C) expand into a broad, diffuse domain within the gynophore and pedicel of older flowers (D). Arrowheads indicate the positions of the sepal AZs. E to J, GUS expression was also detected in seedling roots (F and J) and leaves (G), the axils of floral stems (I), and developing (E) and mature (H) gynoecia.