Plants secrete resins for their protective benefits in response to injury. Resins protect plants from insects and pathogens.[2] Resins confound a wide range of herbivores, insects, and pathogens, while the volatile phenolic compounds may attract benefactors such as parasitoids or predators of the herbivores that attack the plant.[3]
Amberisfossil resin (also called resinite) from coniferous and other tree species. Copal, kauri gum, dammar and other resins may also be found as subfossil deposits. Subfossil copal can be distinguished from genuine fossil amber because it becomes tacky when a drop of a solvent such as acetoneorchloroform is placed on it.[4]
African copal and the kauri gum of New Zealand are also procured in a semi-fossil condition.
Rosin is a solidified resin from which the volatileterpenes have been removed by distillation. Typical rosin is a transparent or translucent mass, with a vitreous fracture and a faintly yellow or brown colour, non-odorous or having only a slight turpentine odour and taste. Rosin is insoluble in water, mostly soluble in alcohol, essential oils, ether, and hot fatty oils. Rosin softens and melts when heated and burns with a bright but smoky flame.
Rosin consists of a complex mixture of different substances including organic acids named the resin acids. Related to the terpenes, resin acid is oxidized terpenes. Resin acids dissolve in alkalis to form resin soaps, from which the resin acids are regenerated upon treatment with acids. Examples of resin acids are abietic acid (sylvic acid), C20H30O2, plicatic acid contained in cedar, and pimaric acid, C20H30O2, a constituent of galipot resin. Abietic acid can also be extracted from rosin by means of hot alcohol.
Rosin is obtained from pines and some other plants, mostly conifers.[5] Plant resins are generally produced as stem secretions, but in some Central and South American species of Dalechampia and Clusia they are produced as pollination rewards, and used by some stingless bee species in nest construction.[6][7]Propolis, consisting largely of resins collected from plants such as poplars and conifers, is used by honey bees to seal small gaps in their hives, while larger gaps are filled with beeswax.[8]
The word resin comes from French resine, from Latin resina "resin", which either derives from or is a cognate of the Greek ῥητίνηrhētínē "resin of the pine", of unknown earlier origin, though probably non-Indo-European.[10][11]
The word "resin" has been applied in the modern world to nearly any component of a liquid that will set into a hard lacquerorenamel-like finish. An example is nail polish. Certain "casting resins" and synthetic resins (such as epoxy resin) have also been given the name "resin".
Some naturally-derived resins, when soft, are known as 'oleoresins', and when containing benzoic acidorcinnamic acid they are called balsams. Oleoresins are naturally-occurring mixtures of an oil and a resin; they can be extracted from various plants. Other resinous products in their natural condition are a mix with gum or mucilaginous substances and known as gum resins. Several natural resins are used as ingredients in perfumes, e.g., balsams of Peru and tolu, elemi, styrax, and certain turpentines.[5]
Other liquid compounds found inside plants or exuded by plants, such as sap, latex, or mucilage, are sometimes confused with resin but are not the same. Saps, in particular, serve a nutritive function that resins do not.
Plant resins are valued for the production of varnishes, adhesives, and food glazing agents. They are also prized as raw materials for the synthesis of other organic compounds and provide constituents of incense and perfume. The oldest known use of plant resin comes from the late Middle Stone Age in Southern Africa where it was used as an adhesive for hafting stone tools.[12]
Resin extraction – Process of collecting sap or resin from pine trees
Balsam of Peru – Type of tree balsam – used in food and drink for flavoring, in perfumes and toiletries for fragrance, and in medicine and pharmaceutical items.
Mastic (plant resin) – Resin traditionally obtained from the mastic tree on the island of Chios
Kino (gum) – plant gumPages displaying wikidata descriptions as a fallback
Biodegradable – Decomposition by living organismsPages displaying short descriptions of redirect targets – plant resins are naturally biodegradable in many circumstances.
Resin casting – method of plastic casting where a mold is filled with a liquid synthetic resin, which then hardens. It is primarily used for small-scale production like industrial prototypes and dentistryPages displaying wikidata descriptions as a fallback
Polyresin – Type of synthetic resinPages displaying short descriptions of redirect targets
^"resin". IUPAC Compendium of Chemical Terminology. 3.0.1 (3rd ed.). International Union of Pure and Applied Chemistry. 2019. doi:10.1351/goldbook.RT07166.
^Bittrich, V.; Amaral, Maria C. E. (1996). "Flower morphology and pollination biology of some Clusia species from the Gran Sabana (Venezuela)". Kew Bulletin. 51 (4): 681–694. Bibcode:1996KewBu..51..681B. doi:10.2307/4119722. JSTOR4119722.
^Gonçalves-Alvim, Silmary de Jesus (2001). "Resin-collecting bees (Apidae) on Clusia palmicida (Clusiaceae) in a riparian forest in Brazil". Journal of Tropical Ecology. 17 (1): 149–153. doi:10.1017/s0266467401001092. S2CID85842020.