Answer
This change due to flooding loosens the plant cell walls (lower pH), which in turn allows cells to expand/grow. This then lower the pressure inside the cells, which induces wilting.
Work Step by Step
This is an interesting example since the wilting does not involve too much water but, rather, less. Use the three facts given in the question to scan the chapter looking for some connection to something that would lower pressure in the cells and cause wilting.
