Fig. 4.

Charasomes are absent from uneven wound walls. a–d Ligation-induced wound walls. The medium near the ligation site of an internodal cell has an alkaline pH (pink) as visualized by phenol red. Cell deformation and a thick wound wall (arrow) becomes visible after removal of the thread (b). Insets correspond to the images (c) and (d). Charasomes (green FM1-43-fluorescent) are absent from the ligation site ((c), corresponding to the upper inset in (b)) and present between red fluorescent chloroplasts in the adjacent acidic control region ((d), corresponding to the lower inset in (b)). e–k Wound walls (WW) induced by puncturing. A single puncture wound (arrow) located within an acidic region is seen in (e). The optical section through the periphery of the cell shows abundant FM1-43 fluorescent charasomes (arrows) outside the wound plug (WP) which seals the cell wall hole (f). No charasomes are visible in an optical section along the wound wall (encircled in (g)). Green fluorescent particles outside the wound wall are mobile FM1-43-stained organelles (putative endosomes) in the endoplasm. The arrow in the optical longitudinal section through a wound plug in (h) points to a single charasome at the otherwise smooth plasma membrane along the non-fluorescent wound wall. Charasomes are seen between the red fluorescent chloroplasts in the unwounded area (arrow head). Multiple puncture wounds cause an alkalinization of the phenol red-containing medium (i). Few charasomes (green fluorescent after staining with FM1-43) are seen in the wound area (j) in comparison with the unwounded region (k). l–n Wound walls caused by epiphytes. The optical section through the cortical cytoplasm shows numerous FM1-43-stained charasomes (green) between red fluorescent chloroplasts surrounding the wound walls (l). Only few charasomes (arrows in (m)) are present at the inner surface of the wound walls; corresponding DIC image (N). Bars = 1 mm (a, e), 300 μm (i), 150 μm (b) 50 μm (c), 20 μm (d, f, g, j-n), 10 μm (h)