Figure 7.

Cross-linking of cell wall proteins by oxidative burst induced by hypoosmotic or mechanical stress in tobacco cells. A, SDS-PAGE and silver staining of cell wall proteins extracted from untreated cells (lane a), 5 min after cell transfer in isoosmotic medium (lane b), hypoosmotic medium (lane c), hypoosmotic medium containing 20 μm IDP (lane d), after 20 min of mechanical stress in culture medium (lane e) or culture medium containing 20 μm IDP (lane f), after 5 min of in vivo treatment of cells by 1 mm H₂O₂ (lane g) or 5 min of in vitro treatment of proteins by 2 mm H₂O₂ (lane h). B, Western blot of cell wall proteins corresponding to cells transferred in hypoosmotic medium containing 20 μm IDP (a) or hypoosmotic medium without IDP (b). St, Molecular mass standards (in kilodaltons). Arrowheads in A and B indicate the 115-kD bands.