Elaiosomes ( grc, ἔλαιον ''élaion'' "oil" + ''sóma'' "body") are fleshy structures that are attached to the

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s of many

plant Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...

species. The elaiosome is rich in

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids incl ...

s and

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, respon ...

s, and may be variously shaped. Many plants have elaiosomes that attract ants, which take the seed to their nest and feed the elaiosome to their

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...

e. After the larvae have consumed the elaiosome, the ants take the seed to their waste disposal area, which is rich in nutrients from the ant

frass Frass refers loosely to the more or less solid excreta of insects, and to certain other related matter. Definition and etymology ''Frass'' is an informal term and accordingly it is variously used and variously defined. It is derived from the G ...

and dead bodies, where the seeds germinate. This type of seed dispersal is termed myrmecochory from the Greek "ant" (myrmex) and "circular dance" (khoreíā). This type of symbiotic relationship appears to be mutualistic, more specifically dispersive mutualism according to Ricklefs, R.E. (2001), as the plant benefits because its seeds are dispersed to favorable germination sites, and also because it is planted (carried underground) by the ants. Elaiosomes develop in various ways either from seed tissues (chalaza, funiculus, hilum, raphe-antiraphe) or from fruit tissues (exocarp, receptacle, flower tube, perigonium, style or spicule). The various origins and developmental pathways apparently all serve the same main function, i.e. attracting ants. Because elaiosomes are present in at least 11,000, but possibly up to 23,000 species of plants, elaiosomes are a dramatic example 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 ...

in flowering plants.

Caruncle

The particular elaiosome in the spurge 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, ...

'' is called caruncle (

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 ...

''caruncula'' "wart"). Seeds that have a caruncle are ''carunculate'', seed that do not have a caruncle are ''ecarunculate''.

List

A fully referenced current list of plants that have seeds with elaiosomes can be found in Lengyel ''et al.'' (2010). *'' Chelidonium majus'' (greater celandine) *'' Claytonia virginica'' *'' Cnidoscolus urens'' *'' Corydalis'' *'' Dicentra'' (bleeding-heart, Dutchman's breeches) *'' Hyacinthus'' (hyacinth) *''

Myrtus ''Myrtus'' (commonly called myrtle) is a genus of flowering plants in the family Myrtaceae. It was first described by Swedish botanist Linnaeus in 1753. Over 600 names have been proposed in the genus, but nearly all have either been moved ...

'' (myrtle) *'' Ricinus communis'' (castor oil plant) *'' Sanguinaria canadensis'' (Bloodroot) *'' Trillium'' *'' Viola'' (violet)

References

{{reflist, 1

External links

*http://waynesword.palomar.edu/plaug99.htm#antdispersal Fruit morphology Insect ecology

Caruncle

List

See also

References

External links