Mucilage

File:Drosera anglica ne4.jpg

A sundew with a leaf bent around a fly trapped by mucilage.

Mucilage is a thick gluey substance produced by most plants and some microorganisms. Mucilage is an exopolysaccharide—a polymer composed of sugar residues and secreted by a microorganism into the surrounding environment. The substance covers the outside of, for example, unicellular or filamentous green algae and cyanobacteria. Amongst the green algae especially, the group Volvocales are known to produce exopolysaccharides in a certain part of their life cycle.

Mucilage in plants is thought to aid in water storage and seed germination, and to act as a membrane thickener and food reserve. Mucilage has a unique purpose in some carnivorous plants. The plant genera Drosera (Sundews), Pinguicula, and others have leaves studded with mucilage-secreting glands, and use a "flypaper trap" to capture insects.

Exopolysaccharides are the most stabilising factor for microaggregates and are widely distributed in soils. Therefore exopolysaccharide-producing "soil algae" play a vital role in the ecology of the world's soils.

Human uses

Mucilage is edible, but tastes rather bland. It is used in medicine for its demulcent properties. Traditionally marshmallows were made from the extract of the mucilaginous root of the marshmallow plant and due to the demulcent nature of the extract, worked as a cough suppressant. Some carnivorous plants with mucilage are used for the traditional production of a dairy product in Sweden, called filmjölk.

An adhesive

Mucilage is also a term for an adhesive composed of a solution of a sticky vegetable product or vegetable gum in water, used primarily to seal paper (e.g., postage stamps and envelope flaps).de:Schleimstoffenl:Mucilage