What Are Cavities Located Within Plant Cells That Store Food?

Physical Characteristics

• Plant cells contain various different organelles, which are encased in a membrane to keep them separate from the other parts of the cell. The vacuole membrane is called a tonoplast. Over time, the membranes of small vacuoles fuse together to form one large tonoplast. In most cells, the large central vacuole is so large that it takes up most of the room inside the cell and is surrounded by only an outer plasma membrane and a thin layer of cytoplasm (the liquid that the organelles live in.)

Storage Mechanism

• The membrane around the compartment does not allow all of the substances in the cytoplasm inside the vacuole. Instead, it transports desirable substances such as minerals and salts from one side of the membrane to another, along with water molecules, and blocks other molecules from entering. This means that the concentration of certain molecules is much higher on the inner side of the membrane than it is on the outside.

Food

• The central vacuole usually holds the food products from the cell's metabolic processes as well as the trace elements the plant needs. Cells that need a supply of food for future growth, such as those in seeds and the organs of the plant that need to grow larger, use the vacuoles as storage areas for proteins and for carbohydrate energy sources. Examples of the proteins in the vacuole include globulins, and for cereal seeds, prolamin. These proteins are storage proteins, which means that the plant uses them primarily as sources of amino acids to make different proteins when necessary.

Other Functions

• The vacuole acts as part of the structural scaffold of the cell, as it usually is full of water and so exerts pressure on the outside of the cell to prevent it collapsing. The effect of vacuoles on structure is most obvious when a wilted plant receives water after a drought and grows tall and strong again.

  In one cell, a vacuole can also perform essential functions, such as storing waste products of the plant, which can be bitter-tasting to act as a deterrent to herbivores. A vacuole can also break down foreign molecules to prevent infection, or contain pigments which color parts of the plant to attract bird and insects for pollination purposes.