Fig. 6.

SAM and RAM defects in late stage gct and cct embryos. (A-E) Bent cotyledon stage wild-type, gct and cct embryos: 86% (n=151) of late stage gct embryos have an enlarged SAM (B); 14% (n=151) of late stage gct embryos lack the small vacuolated cells and layered tissue organization characteristic of the SAM (C); 94% (n=171) of late stage cct embryos have an enlarged SAM (D); 6% (n=171) of late stage cct embryos lack a SAM (E). (F) Medial section of wild-type SAM contains an average of 25±1 cells, (n=15). (G) Medial section of enlarged gct SAM contains an average of 68±5 cells (n=15). (H) gct embryo with large vacuolated cells in place of the SAM. (I) Medial section of enlarged cct SAM contains an average of 66±8 cells (n=15). (J) cct embryo with large vacuolated cells in place of the SAM. (K) Medial optical section of a wild-type RAM. (L) Of gct embryos, 86% had a slightly disorganized root cap and extra cells in RAM (n=84). (M) In addition, 14% of gct embryos lacked most cells of the root cap (n=84). (N) Of cct embryos, 100% (n=81) had a slightly disorganized root cap and extra cells in RAM. (O-Q) Hypocotyl of wild-type (O), gct (P) and cct (Q) embryos. Percentages in B-E refer to mutant embryos only, which are easily distinguished at late stages by their meristem phenotype. In A-E, the location of the SAM and RAM are shown in boxes. Original cleared images and tracings of the SAM, RAM or hypocotyl are shown in F-Q. The SAM was defined as the region bounded by vascular tissue. A-E and F-Q shown at equal magnification. Scale bars: 40 μm in A; 10 μm in F. Asterisks indicate quiescent center cells of root meristem. co, cortex; en, endodermis; ep, epidermis; lrc, lateral root cap; p, pericycle; v, vascular tissue; x, extra RAM cells.