In a well watered habitat this would not be a problem for the plant. Soil water would be freely available and the atmosphere would be relatively humid from evaporation of soil water. The need to conserve water would not be great in these conditions. In fact, plants adapted for life in or near permanent water have either unusual positioning of stomata, or very little change in stomatal aperture each day. If the soil around the roots is dry, failure to replace water lost is inevitable.
Water diffuses out of the plant cell vacuoles, the cell become flaccid, and the plant wilts.
Many Australian plants have adaptations for hot dry summers, such as that of 1996-97. These plants are able to survive because of the compromise their guard cells achieve. Frequently other adaptations such as thick waxy cuticles and leaves which hang down, or are narrow and short, and have reduced exposure to the direst sun are also seen in Australian plants from arid regions. Guard cells, unlike other epidermal cells, possess chloroplasts and are therefore able to perform photosynthesis . In the presence of light, photosynthesis begins in the guard cells and the other photosynthetic cells of the leaf.