When a seed comes into contact with water it absorbs it and swells up. The seed imbibes water. Imbibe means ‘to drink’. Do not get this process mixed up with osmosis, it is not the same thing!

This is possible because of the presence of colloidal particles in the testa which attract water and cause the seed to swell.

Watch this video, paying particular attention to the seeds imbibing before they start to germinate.

Factors limiting imbibition

Temperature: The rate of imbibition increases with temperature increase.

Solute concentration: The purer the water is, the higher the rate of imbibition. If the water is high in solutes (dissolved compounds) then the rate of imbibition will be low.

Image of tree seeds imbibing

Why is imbibition so important?

  • It plays a key role in the initial stage of water absorption by roots when seedlings are young.
  • It initiates seed germination.
  • It plays a role in adhering water to xylem tissues.
  • It helps fruits to retain water.
  • It plays a major role in young and actively growing tissues.


  • SFC logo
  • UHI logo
  • Funded as part of the Scottish Funding Council's curriculum development unit cost model project. Developed by the Educational Development Unit, University of the Highlands and Islands.


UHI provides links to external sources of information and may refer to specific Web sites, products, processes or services within this resource. Such references are examples and are not endorsements and whilst every effort is taken to ensure the accuracy of information provided UHI is not responsible for any of the content or guidance. You are advised to exercise caution.

Information on social media websites may also be provided. Staff using social media websites must comply with the University’s social media policy. It is recommended that you fully understand the terms and conditions of use before using these sites and that you take steps to protect personal or sensitive data.

PDF version.