Elaiosomes (Greek élaion "oil" and sóma "body") are fleshy structures that are attached to the seeds of many plant species. The elaiosome is rich in lipids and proteins, and may be variously shaped. Many plants have elaiosomes to attract ants, which take the seed to their nest and feed the elaiosome to their larvae. 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 and dead bodies, where the seeds germinate. This type of seed dispersal is termed myrmecochory from the Greek "ant" (myrmex) and "dispersal" (kore). This type of symbiotic relationship appears to be mutualistic, 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, mycropyle, raphe-antiraphe) or from fruit tissues (exocarp, receptacle, flower tube, perigonium, style or spicule)^[1]. 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 in flowering plants ^[2].

Elaioplasts is another name for fat-producing cells (plastids).

[edit] Caruncle

Caruncle

The particular elaiosome in the spurge family Euphorbiaceae is called caruncle (Latin caruncula "wart"). Seeds that have a caruncle are carunculate, seed that do not have a caruncle are ecarunculate.

[edit] List

A fully referenced current list of plants that have seeds with elaiosomes can be found in a reference.^[2]

• Sanguinaria canadensis (Bloodroot)
• Trillium
• Dicentra (bleeding-heart, Dutchman's breeches)
• Corydalis
• Chelidonium majus (greater celandine)
• Hyacinthus (hyacinth)
• Myrtus (myrtle)

[edit] Gallery

Afzelia africana seed

Trillium recurvatum seeds

Carunculate seed of Ricinus communis (Castor beans)

Carunculate seed of Euphorbia mafingensis

[edit] See also

• Aril
• Capitulum, a similar appendage with similar purposes found in stick insect eggs.
• Myrmecochory

[edit] References

[edit] External links

• http://waynesword.palomar.edu/plaug99.htm#antdispersal