Editing Plasmolysis (section)

== Plasmolysis ==
[[Image:Turgor pressure on plant cells diagram.svg|thumb|300px|right|Plant cell under different environments]] If a plant cell is placed in a [[Tonicity#Hypertonic solution|hypertonic]] solution, the plant cell loses water and hence [[turgor]] pressure by plasmolysis: pressure decreases to the point where the protoplasm of the cell peels away from the cell wall, leaving gaps between the cell wall and the membrane and making the plant cell shrink and crumple.  A continued decrease in pressure eventually leads to [[cytorrhysis]] – the complete collapse of the cell wall. Plants with cells in this condition wilt. After plasmolysis the gap between the cell wall and the cell membrane in a plant cell is filled with [[hypertonic]] solution. This is because as the solution surrounding the cell is hypertonic, [[exosmosis]] takes place and the space between the cell wall and cytoplasm is filled with solutes, as most of the water drains away and hence the concentration inside the cell becomes more hypertonic. There are some mechanisms in plants to prevent excess water loss in the same way as excess water gain. Plasmolysis can be reversed if the cell is placed in a [[hypotonic]] solution. [[Stoma]]ta close to help keep water in the plant so it does not dry out. [[Wax]] also keeps water in the plant. The equivalent process in animal cells is called [[crenation]]. 
The liquid content of the cell leaks out due to exosmosis. The cell collapses, and the cell membrane pulls away from the cell wall (in plants). Most animal cells consist of only a [[Lipid bilayer|phospholipid bilayer]] ([[plasma membrane]]) and not a cell wall, therefore shrinking up under such conditions.

Plasmolysis only occurs in extreme conditions and rarely occurs in nature. It is induced in the laboratory by immersing cells in strong [[Saline (medicine)|saline]] or sugar (sucrose) solutions to cause [[exosmosis]], often using ''[[Elodea]]'' plants or [[onion epidermal cell]]s, which have colored cell sap so that the process is clearly visible.  [[Methylene blue]] can be used to stain plant cells.

Plasmolysis is mainly known as shrinking of cell membrane in hypertonic solution and great pressure.

Plasmolysis can be of two types, either concave plasmolysis or convex plasmolysis. Convex plasmolysis is always irreversible while concave plasmolysis is usually reversible.<ref name="[1]" /> During concave plasmolysis, the plasma membrane and the enclosed protoplast partially shrinks from the cell wall due to half-spherical, inwarding curving pockets forming between the plasma membrane and the cell wall. During convex plasmolysis, the plasma membrane and the enclosed protoplast shrinks completely from the cell wall, with the plasma membrane's ends in a symmetrically, spherically curved pattern.<ref name="[1]" />