Question

describe plasmolysis

Answer 1

Plasmolysis is the process in which cells lose water in a hypertonic solution. The reverse process, cytolysis, can occur if the cell is in a hypotonic solution resulting in a lower external osmotic pressure and a net flow of water into the cell. 

Answer 2

The collapse of cell wall of cell when water is lost is called plasmolysis.

Actually when a cell is sorrounded by medium having the concentration solute more than the solvent then exosmosis takes place resultaing in the transfer of water from cell to medium to maintain equilibrium.