Plant vacuoles perform several different functions and are essential for the plant cell. The large central vacuoles of mature plant cells provide structural support, and they serve other functions, such as protein degradation and turnover, waste disposal, storage of metabolites, and cell growth. A unique feature of the plant vacuolar system is the presence of different types of vacuoles within the same cell. The current knowledge about the vacuolar compartments in plants and green algae is summarized and a hypothesis is presented to explain the origin of multiple types of vacuoles in plants.