root pressure

noun

Botany.

1. osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves.

root pressure

1. Pressure produced in the roots of plants, causing exudation of sap from cut stems and guttation of water from leaves. The pressure is generated by the concentration of solutes in the xylem of the root and stem, which in turn causes water to move into the xylem by osmosis.

Word History and Origins

Origin of root pressure¹

First recorded in 1870–75

Example Sentences

Professor Craig: That is a very difficult question, because it isn't settled at the present time what credit we should give to capillarity and what to root pressure in sap circulation.

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CRANE: It is very largely root pressure.

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