Figure 1

Progression of developmental PCD within a lace plant leaf, stages (1-5). Delineation of leaf morphogenesis in lace plant leaves as PCD progresses. A) Whole plant growing in sterile culture in a magenta box filled with liquid and solid Murashige and Skoog (MS) medium. B) Stage 1, or pre-perforation lace plant leaf, note the abundance of the pink pigment anthocyanin within most cells of the leaf. Also note that one full areole is shown bound by vascular tissue. C) Stage 2, or "window" stage lace plant leaf, note the distinct cleared area in the center of the vasculature tissue indicating a loss of pigments anthocyanin and chlorophyll. D) Stage 3, or perforation formation lace plant leaf. The cells in the center of the cleared window have begun to break away, forming a hole in the center of the areole. E) Stage 4, or perforation expansion lace plant leaf, note that cell death has stopped approximately 4-5 cells from the vascular tissue. F) Stage 5, or a completed perforation in a lace plant leaf. The cells bordering the perforation have transdifferentiated to become epidermal cells. Scale bars (A) = 1 cm; (B) = 200 μm; (C-F) = 500 μm.