The Lace Plant, or Aponogeton madagascariensis. (A) Experimental lace plant in a magenta box containing liquid and solid MS medium. (B) Stage 2, or ‘window’ stage leaf. Note the pink colouration, due to the pigment anthocyanin in the plant cell vacuole. (C) Subdivision of a single areole of a window stage leaf. Surrounding the areole is vascular tissue, or the veins of the leaf (outside the white square). The first delineation are cells that will not undergo PCD, or the NPCD cells, and are used as control cells (between the white and the red rectangles). These cells are markedly pink due to the pigment anthocyanin. The next grouping of cells are those in the earliest stage of PCD, or the EPCD stage cells (between the red and the blue rectangles). These cells are normally green, marking the presence of chlorophyll. Finally, the cells in the latest stage of PCD, or LPCD stage cells, are in the centre of the areole (inside the blue rectangles). These cells are usually transparent, indicating that pigments have been degraded. (D-G) Progression of window development within a section of an areole captured during long-term live cell imaging approximately at times 0, 12, 36, and 60 hours, respectively. Arrows indicate cells that were initially seen with chlorophyll pigmentation (D), reduced pigmentation (E and F) and collapsed PM (G). Microscope settings remained constant throughout observation. Scale bars: A-B = 1 cm, C = 250 μm, D-F = 30 μm, G = 40 μm.