Class 11 Biology Transport In Plants Plasmolysis


  • The process in which water moves out of the cell, and the cell membrane of a plant cell shrinks away from its cell wall, is called plasmolysis.
  • If the external solution balances the osmotic pressure of the cytoplasm, it is said to be isotonic.
  • If the external solution is more dilute than the cytoplasm, it is hypotonic.
  • If the external solution is more concentrated than the cytoplasm, it is hypertonic.
  • When a cell is placed in an isotonic solution, there is no net flow of water towards the inside or outside.
  • When water flows into the cell and out of the cell and are in equilibrium, the cells are said to be flaccid.
  • When the cells are placed in a hypotonic solution, water diffuses into the cell causing the cytoplasm to build up a pressure against the wall, that is called turgor pressure.


Fig. Hypotonic, isotonic, hypertonic solution

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