Figure 10

Cytological events associated with wound-induced cell death. (A) Unwounded cell. Fusiform bodies outlined in blue, cytoplasmic GFP-Nit1 in red, ER and nuclear envelope membranes shown in green, ER lumen contents shown in gray and nuclear lumenal contents shown in yellow, plasma membrane in black. (B – F) Post-wound events. (B)The earliest events documented are the collapse of fusiform bodies and nuclear hypertrophy. (C) Shortly after these early rapid events, aggregation of GFP-Nit1 occurs and the nucleus initiates contraction concurrent with separation of the nuclear envelope. (D) As contraction and lobing continue, contents of the nucleoplasm leak into the cytosol. It is currently unknown if this release is general or if there is specificity to the particular contents lost. (E) Later, after nuclear contraction has largely ceased, the tubular ER network that is still intact undergoes a dramatic loss of integrity and degenerates, forming vesicular structures. (F) This is followed later by intense staining of nuclei by propidium iodide and extensive cell shrinkage. Propidium iodide staining of nuclei is indicated in (F) by the red color of the nucleus.