Fig. 2. Patterns of GUS– sector sharing seen in mature chimeric plants after sector induction at the two-apical-cell stage of embryogenesis. All plants are shown with clockwise phyllotaxy to permit easy visual comparison of sector sharing patterns. GUS– cell sectors are visualized as white tissue after clearing plants with ethanol while GUS+ cells retain blue coloration (A-H). Most GUS– sectors included all cells in one cotyledon and extended into physically adjacent organs (A,B) but many sectors also included one whole cotyledon and either the left or right margin of the other cotyledon (C). Rarer sectors extended either between cotyledons on the same side of the frontal longitudinal plane (D) or extended between the cotyledons but crossed the frontal plane (E). Most chimeras had sector boundaries that either separated the left and right margins of leaf 1 or leaf 2 (A,E,G-H) or separated the left and right margins of both leaf 1 and leaf 2 (B,F) which is reflected in the map as a tendency for GUS– sectors not to be shared between organs that lie across the sagittal longitudinal plane of the embryo. C1 and C2, cotyledon 1 and 2; 1-4, true leaves 1-4.