Central vacuole acts as the storage of various substances (water and other ions) and makes the plant turgid.
In a mature living plant, the cell usually contain a large central vacuole (as much as 90% volume), whose contents, the vacuolar sap, contribute to the solute potential of the cell. Central vacuoles are bounded by vacuolar membranes which form the inner boundaries of the living part of the cell. Vacuolar membranes are alike in construction and function to plasma membranes.
The cytoplasm of the root hair contains a large central vacuole filled with cell sap.
Image Reference: http://micro.magnet.fsu.edu/cells/plants/images/plantvacuolesfigure1.jpg
