Fig. 1.

Senescence, wound-induced browning and cell death in lettuce fresh-cuts, stored at 4 °C a1 Slight browning at the cut edge (non-labelled tissue). a2 H₂O₂ production at the area showing initial browning, DAB staining, chlorophyll removed—the tissue appears in brown due to the presence of H₂O₂. a3 Cell death surrounding an injured site; following Evans Blue staining the dead cells appear in blue (a1–3), day 2. b Tissue browning in area adjacent a site injured with a cork borer, day 4. c Senescing shred on day 7; note sites in which cells have disappeared (arrows); inset shows area with vanished cells. d Senescing shred on day 9; visible is severe browning close to the cut edge, a large necrotic lesion of entirely necrotized tissue and disappearance of cells inside and in vicinity to it (inset, arrows). Scale bars = a2 500 μm, a3 50 μm, c (inset) 100 μm