Production of supernumerary endodermal cell layers is associated with accumulation of 4C and depletion of 2C cells. Supernumerary endodermal cell layers were produced by transgenic expression of SHR under the control of the SCR promoter, and these layers were identified via expression of HTA6-GFP under the control of the SCR promoter. A. Confocal analysis of the transgenic plants. B. C-value distributions of GFP-positive and -negative nuclei as determined through biparametric flow analysis (axis designations as described in the Legend to Figure 4). C. Classification of the proportions of nuclei within the various C-value classes for non-transgenic controls (WT), for all nuclei within transgenic plants producing supernumerary endodermal cells (SN-SCR), and for GFP-positive nuclei (GFP+) within these same transgenic plants.