What would be the pressure potential of a flaccid cell??which organisms other than plants possess cell wall??

 the pressure potential can be negative, zero, or positive. A plasmolyzed cell, where the plasma membrane has pulled away from the cell wall, has a negative pressure potential. In contrast, a turgid cell in hypotonic medium has a positive pressure potential.

The organisms that possess cell wall are:

Some species of Archea have cell walls, bacteria posesses cell wall.