FIGURE 3.

Gradual loss of the old plasma membrane during sporulation. An asynchronously sporulating culture was exposed briefly to the lipophilic dye FM™4–64. The stage of sporulation is labelled and was estimated based on spore and ascus wall appearance by transmitted light. Inset, an illustration of the arrangement of spores in a tetrahedral ascus with all six interspore bridges (red circles) intact and in a rhomboid ascus in which one of the bridges has broken (dashed red circle) as an ascus flattens under a coverslip