Latex is an

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...

(stable dispersion) of

polymer A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

microparticles in water. Latexes are found in

nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...

, but synthetic latexes are common as well. In nature, latex is found as a

milky Milky is an Italian dance music production group consisting of producers Giordano Trivellato and Giuliano Sacchetto, with Italian singer Giuditta serving as their lead singer on their album ''Star''.fluid found in 10% of all

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s (angiosperms). It is a complex emulsion that coagulates on exposure to air, consisting of

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

s, starches, sugars,

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...

s, and gums. It is usually exuded after tissue injury. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Since the 17th century, latex has been used as a term for the fluid substance in plants, deriving from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word for "liquid". It serves mainly as defense against

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s. Latex is not to be confused with

plant sap Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a se ...

; it is a distinct substance, separately produced, and with different functions. The word latex is also used to refer to natural latex

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, an ...

, particularly non-

vulcanized Vulcanization (British: Vulcanisation) is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to inclu ...

rubber. Such is the case in products like latex gloves, latex condoms and

latex clothing Latex rubber is used in the manufacture of many types of clothing. It has traditionally been used to make protective clothing, including gas masks and Wellington boots. Mackintoshes have traditionally been made from rubberized cloth. However, ...

Biology

Articulated laticifers

The cells ( laticifers) in which latex is found make up the laticiferous system, which can form in two very different ways. In many plants, the laticiferous system is formed from rows of cells laid down in the

meristem The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...

of the stem or

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...

. The cell walls between these cells are dissolved so that continuous tubes, called latex vessels, are formed. Since these vessels are made of many cells, they are known as ''articulated laticifers''. This method of formation is found in the

poppy family The Poppy Family was a Canadian psychedelic pop group based in Vancouver. They had a number of international hit records in the late 1960s and early 1970s. Career Seventeen-year-old Susan Pesklevits met Terry Jacks in the mid-1960s when he ...

and in the

trees (

Para rubber tree ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge family Euphorbiaceae originally native to the Amazon basin, but is now pan ...

, members of the family

Euphorbiaceae Euphorbiaceae, the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of a genus in the family. Most spurges, such as '' Euphorbia paralias'', are herbs, but some, ...

, members of the mulberry and fig family, such as the Panama rubber tree ''

Castilla elastica ''Castilla elastica'', the Panama rubber tree, is a tree native to the tropical areas of Mexico, Central America, and northern South America. It was the principal source of latex among the Mesoamerican peoples in pre-Columbian times. The latex g ...

''), and members of the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

. For instance, ''

Parthenium argentatum ''Parthenium argentatum'', commonly known as the guayule ( or , as in Spanish), is a perennial woody shrub in the family Asteraceae that is native to the rangeland area of the Chihuahuan Desert; including the southwestern United States and northe ...

'' the guayule plant, is in the tribe

Heliantheae The Heliantheae (sometimes called the sunflower tribe) are the third-largest tribe in the sunflower family (Asteraceae). With some 190 genera and nearly 2500 recognized species, only the tribes Senecioneae and Astereae are larger. The name is ...

; other latex-bearing Asteraceae with articulated laticifers include members of the

Cichorieae The Cichorieae (also called Lactuceae) are a tribe in the plant family Asteraceae that includes 93 genera, more than 1,600 sexually reproductive species and more than 7,000 apomictic species. They are found primarily in temperate regions of the E ...

, a clade whose members produce latex, some of them in commercially interesting amounts. This includes ''

Taraxacum kok-saghyz ''Taraxacum kok-saghyz'', often abbreviated as ''TKS'' and commonly referred to as the Kazakh dandelion, rubber root, or Russian dandelion, is a species of dandelion native to Kazakhstan, Kyrgyzstan and Uzbekistan, that is notable for its product ...

'', a species cultivated for latex production.

Non-articulated laticifers

In the

milkweed ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans ...

and

spurge ''Euphorbia'' is a very large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae. "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae (in deference to t ...

families, on the other hand, the laticiferous system is formed quite differently. Early in the development of the seedling, latex cells differentiate, and as the plant grows these latex cells grow into a branching system extending throughout the plant. In many euphorbs, the entire structure is made from a single cell – this type of system is known as a ''non-articulated laticifer'', to distinguish it from the multi-cellular structures discussed above. In the mature plant, the entire laticiferous system is descended from a single cell or group of cells present in the embryo. The laticiferous system is present in all parts of the mature plant, including roots, stems, leaves, and sometimes the

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

s. It is particularly noticeable in the cortical tissues. Latex is usually exuded as a white liquid, but is some cases it can be clear, yellow or red, as in

Cannabaceae Cannabaceae is a small family of flowering plants, known as the hemp family. As now circumscribed, the family includes about 170 species grouped in about 11 genera, including ''Cannabis'' (hemp), '' Humulus'' (hops) and '' Celtis'' (hackberries ...

Productive species

Latex is produced by 20,000

species from over 40

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

. These include both dicots and

monocots Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of ...

. Latex has been found in 14 percent of tropical plant species, as well as six percent of temperate plant species. Several members of the fungal kingdom also produce latex upon injury, such as ''

Lactarius deliciosus ''Lactarius deliciosus'', commonly known as the saffron milk cap and red pine mushroom, is one of the best known members of the large milk-cap genus '' Lactarius'' in the order Russulales. It is native to Europe, but has been accidentally introd ...

'' and other milk-caps. This suggests it is the product of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

and has been selected for on many separate occasions.

Defense function

Latex being collected from a tapped rubber tree

Latex functions to protect the plant from herbivores. The idea was first proposed in 1887 by Joseph F. James, who noted that latex

carries with it at the same time such disagreeable properties that it becomes a better protection to the plant from enemies than all the thorns, prickles, or hairs that could be provided. In this plant, so copious and so distasteful has the sap become that it serves a most important purpose in its economy.

Evidence showing this defense function include the finding that slugs will eat leaves drained of their latex but not intact ones, that many insects sever the veins carrying latex before they feed, and that the latex of ''

Asclepias humistrata ''Asclepias humistrata'', the sandhill milkweed, is a species of milkweed plant. It is also known as pinewoods milkweed and pink-veined milkplant. It belongs in the subfamily Asclepiadoideae. It is native to the southeastern United States. It ...

'' (sandhill

) kills by trapping 30% of newly hatched monarch butterfly caterpillars. Other evidence is that latex contains 50–1000× higher concentrations of defense substances than other plant tissues. These toxins include ones that are also toxic to the plant and consist of a diverse range of chemicals that are either poisonous or " antinutritive." Latex is actively moved to the area of injury; in the case of ''

Cryptostegia grandiflora ''Cryptostegia grandiflora'', commonly known as rubber vine, is a woody-perennial vine that is native to south-west Madagascar. It is also a significant weed in northern Australia, sometimes regarded as the worst weed in all of Australia. It ...

'', latex more than 70 cm from the site of injury is mobilized. The large hydrostatic pressure in this vine enables an extremely high flow rate of latex. In a 1935 report the botanist

Catherine M. Bangham Katherine, also spelled Catherine, and Catherina, other variations are feminine Given name, names. They are popular in Christian countries because of their derivation from the name of one of the first Christian saints, Catherine of Alexandria ...

observed that "piercing the fruit stalk of ''Cryptostegia grandiflora'' produced a jet of latex over a meter long, and maintained

his jet His or HIS may refer to: Computing * Hightech Information System, a Hong Kong graphics card company * Honeywell Information Systems * Hybrid intelligent system * Microsoft Host Integration Server Education * Hangzhou International School, in ...

for several seconds." The clotting property of latex is functional in this defense since it limits wastage and its stickiness traps insects and their mouthparts. While there exist other explanations for the existence of latex including storage and movement of plant nutrients, waste, and maintenance of water balance that " sentially none of these functions remain credible and none have any empirical support".

Applications

Opium pod cut to demonstrate fluid extraction1

The latex of many species can be processed to produce many materials. *

Balatá ''Manilkara bidentata'' is a species of ''Manilkara'' native to a large area of northern South America, Central America and the Caribbean. Common names include bulletwood, balatá, ausubo, massaranduba, quinilla, and (ambiguously) " cow-tree". D ...

and

gutta percha Gutta-percha is a tree of the genus '' Palaquium'' in the family Sapotaceae. The name also refers to the rigid, naturally biologically inert, resilient, electrically nonconductive, thermoplastic latex derived from the tree, particularly from ...

latex contain an inelastic polymer related to rubber. * Chicle and jelutong tree latex was used in

chewing gum Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. Its t ...

Personal and healthcare products

Natural rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

is the most important product obtained from latex; more than 12,000 plant species yield latex containing rubber, though in the vast majority of those species the rubber is not suitable for commercial use. This latex is used to make many other products including mattresses, gloves, swim caps, condoms,

catheter In medicine, a catheter (/ˈkæθətər/) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgi ...

s and

balloon A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...

Opium and opiates

Dried latex from the opium poppy is called opium, the source of several useful analgesic

s such as codeine,

thebaine Thebaine (paramorphine), also known as codeine methyl enol ether, is an opiate alkaloid, its name coming from the Greek Θῆβαι, '' Thēbai'' (Thebes), an ancient city in Upper Egypt. A minor constituent of opium, thebaine is chemically similar ...

, and

morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. T ...

, the latter two of which can then further be used in the synthesis and manufacture of other (typically stronger) opioids for medicinal use, and of heroin for the

illegal drug trade The illegal drug trade or drug trafficking is a global black market dedicated to the cultivation, manufacture, distribution and sale of prohibited drugs. Most jurisdictions prohibit trade, except under license, of many types of drugs throug ...

. The opium poppy is also the source of medically useful non-analgesic alkaloids, such as

papaverine Papaverine (Latin '' papaver'', "poppy") is an opium alkaloid antispasmodic drug, used primarily in the treatment of visceral spasms and vasospasms (especially those involving the intestines, heart, or brain), occasionally in the treatment of e ...

and

noscapine Noscapine (also known as Narcotine, Nectodon, Nospen, Anarcotine and (archaic) Opiane) is a benzylisoquinoline alkaloid, of the phthalideisoquinoline structural subgroup, which has been isolated from numerous species of the family Papaveraceae ( ...

Clothing

Latex is used in many types of

clothing Clothing (also known as clothes, apparel, and attire) are items worn on the body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin sheets of materials and natural ...

. Worn on the body (or applied directly by painting), it tends to be

skin-tight A skin-tight garment is a garment that is held to the skin usually by elastic tension using some type of stretch fabric. Commercial stretch fabrics ('elastomerics') such as spandex or elastane (widely branded as 'Lycra') came onto the market i ...

, producing a "second skin" effect.

Industrial and biological applications from synthetic latexes

Synthetic latexes are used in

coating A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. Pow ...

s (e.g., latex paint) and glues because they solidify by

coalescence Coalescence may refer to: * Coalescence (chemistry), the process by which two or more separate masses of miscible substances seem to "pull" each other together should they make the slightest contact * Coalescence (computer science), the merging of ...

of the polymer particles as the water evaporates. These synthetic latexes therefore can form films without releasing potentially toxic organic solvents in the environment. Other uses include cement additives and to conceal information on

scratchcard A scratchcard (also called a scratch off, scratch ticket, scratcher, scratchum, scratch-it, scratch game, scratch-and-win, instant game, instant lottery, scratchie, lot scrots, or scritchies) is a card designed for competitions, often made of ...

s. Latex, usually

styrene Styrene () is an organic compound with the chemical formula C6H5CH=CH2. This derivative of benzene is a colorless oily liquid, although aged samples can appear yellowish. The compound evaporates easily and has a sweet smell, although high concen ...

-based, is also used in

immunoassay An immunoassay (IA) is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoass ...

Allergic reactions

Some people only experience a mild allergy when exposed to latex, like

eczema Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...

contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are ...

or developing a

rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, c ...

. Others have a serious

latex allergy Latex allergy is a medical term encompassing a range of allergic reactions to the proteins present in natural rubber latex. It generally develops after repeated exposure to products containing natural rubber latex. When latex-containing medical de ...

, and exposure to latex products such as latex gloves can cause anaphylactic shock. Guayule latex has only 2% of the levels of protein found in '' Hevea'' latexes, and is being researched as a lower-allergen substitute. Additionally, chemical processes may be employed to reduce the amount of antigenic protein in ''Hevea'' latex, yielding alternative materials such as

Vytex Natural Rubber Latex Vytex Natural Rubber Latex (NRL) is a brand of natural rubber latex produced and marketed by Vystar Corporation. Vytex NRL is an alternative material to petroleum-based synthetics and traditional, or Hevea, natural rubber latex. Protein test resu ...

which provide significantly reduced exposure to latex allergens. About half of people with

spina bifida Spina bifida (Latin for 'split spine'; SB) is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, men ...

are also allergic to natural latex rubber, as well as people who have had multiple surgeries, and people who have had prolonged exposure to natural latex.

Microbial degradation

Several species of the microbe genera ''

Actinomycetes The Actinomycetales is an order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycete ...

'', '' Streptomyces'', '' Nocardia'', ''

Micromonospora ''Micromonospora'' is a genus of bacteria of the family Micromonosporaceae. They are gram-positive, spore-forming, generally aerobic, and form a branched mycelium; they occur as saprotrophic forms in soil and water. Various species are sources ...

'', and ''

Actinoplanes ''Actinoplanes'' is a genus in the family Micromonosporaceae. They have aerial mycelia and spherical, motile spores. ''Actinoplanes'' species produce the pharmaceutically important compounds valienamine (a precursor to the antidiabetic drug acar ...

'' are capable of consuming rubber latex. However, the rate of biodegradation is slow, and the growth of bacteria utilizing rubber as a sole carbon source is also slow.