Fig. 5. Bright-field and fluorescent micrographs of stolon tips from colonies of P. carnea. (A–C) A healthy stolon tip (A) from a control colony has numerous cells as visualized by propidium iodide (PI) staining (B), but only a few of these cells exhibit DNA fragmentation as visualized by TUNEL staining (C). (D–F) A regressing stolon tip that was treated for 60 min with 5 mmol l^–1 H₂O₂ (D) also has numerous cells as visualized by PI staining (E), and the majority of these cells exhibit DNA fragmentation as visualized by TUNEL staining (F). Note that the tip of the stolon has regressed in D, E and F, thus, there is no fluorescence in this area in E and F. Scale bar, 25 µm.