a fluid manufactured by the cytoplasm of the living plant cell and filling the cell’s vacuoles.

Cell sap consists of water and various substances that are often in the form of a colloidal suspension. On the average, cell sap has twice the viscosity of water. In dormant seeds and spores the cell sap dehydrates, hydrating again upon germination. Young cells have less cell sap than older ones. The composition of cell sap is specific to families and even to species, depending also on growth conditions, the age of the plant, and the age of the individual cells. Cell sap contains the carbohydrates glucose, fructose, sucrose (grapes, apples, pears, sugar beets), and inulin (dahlia, Jerusalem artichoke), pectins (citrus, currants, apples), and glycosides (hesperidin, amygdalin); tannins; a number of amino acids (leucine, tyrosine); alkaloids (nicotine, anabasine, caffeine); organic acids (oxalic, citric, malic); and inorganic acids. Calcium oxalate crystals are found as inclusions. The cell sap of some marine algae contains iodine and bromine. The color of cell sap is determined by pigments: blue, violet, and red, by anthocyanins; yellow, by anthochlorins; and brown, by anthophaeinin.

The cell sap contributes to the osmotic properties and turgor of the cell and, consequently, to the elasticity of plant tissues and organs. It also serves as a receptacle for the water and various substances that participate in cell metabolism and as a place for the deposit of the end products of metabolism.