What are the functions of the tonoplast

Vacuoles are stretchable cell organelles that mainly occur in plant and fungal cells and act as a storage medium for water (and the nutrients dissolved in it). The term is derived from the Latin "vacuus" (vacuum or empty space). The vacuoles filled with water are usually very clearly visible under the microscope because of their relatively large size. In plant cells, vacuoles usually take up more than 3/4 of the cell interior.

Vacuoles arise during cell growth; more precisely in the course of elongation growth. The elongation growth serves to increase the size of the plant. In contrast to division growth, elongation growth is much more energy efficient.

Variants of the vacuole In the known paramecia, vacuoles also appear in the form of contractile vacuoles. Contractile vacuoles are contracting vesicles that are used to remove water from the cell. To do this, the contractile vacuoles increase and decrease rhythmically, absorbing cell fluid from within and releasing it to the outside of the cell. The influx of water is due to the higher internal osmotic pressure within the cell and is caused by this. The salt concentration inside the cell is therefore higher than in the freshwater surrounding it. Without the presence of the contractile vacuoles, the osmotic pressure inside the cell would be too high and the cell would burst.