Amphicarpy

Amphicarpy is a reproductive strategy that occurs with nine plant families,[1] expressed mostly in species with an annual life cycle.[2] It is characterized by production of two types of fruit, for different ecological roles.[3][4][5][6] It is sometimes restricted to the situation where one fruit type is aerial and the other subterranean (hypogeous),[7] and distinguished from heterocarpy. The word amphicarp is the contraction of the Greek words ἀμφί meaning "of both kinds" and καρπός meaning fruit.[5]

In a typical plant with amphicarpy, one fruit type is underground. These underground fruits usually develop from self-pollinating flowers. The fruits that develop from the aerial flowers may often be the result of cross-pollination.[8]

Plants use this strategy to increase the chance that their genetic material is passed on. It can be referred to as bet hedging in which an organism produces several different phenotypes. Seeds from the underground flowers have low genetic variability (due to their selfing), tend to be larger, and may germinate from within the tissues of the flower, so ensuring that the annual can remain at the site that was suitable to it in the preceding year. Seeds from aerial flowers usually have greater genetic variability, tend to be smaller, and may be spread further. This assists the colonization of new territory, but also helps the exchange of genetic material between populations.[9]

Worldwide, approximately fifty species exhibit amphicarpy, or 0.02% of the known species of flowering plants. Most of these fifty species occur in often disturbed or very stressful circumstances. In Israel, a country that harbors many disturbed habitats, with eight out of a total flora of twenty five hundred species, a much higher percentage of 0.32% is amphicarpic.[10] Species that use amphicarpy include Catananche lutea, Gymnarrhena micrantha and Polygala lewtonii.[9][11][12] Trifolium polymorphum is a perennial, that combines amphicarpy with vegetative reproduction through stolons. It grows in grasslands where its aerial flowers may not come into seed due to herbivores.[13]

References
  1. Cheplick, Gregory Paul (1987). "The ecology of amphicarpic plants". Trends in Ecology & Evolution. 2 (4): 97–101. doi:10.1016/0169-5347(87)90166-2. PMID 21227828.
  2. Greenwood, Paul J.; Harvey, Paul H.; Slatkin, Montgomery (1985). Evolution: Essays in Honour of John Maynard Smith. CUP Archive. p. 149. ISBN 9780521257343.
  3. Beentje, H. & Williamson, J. (2010), The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms, Royal Botanic Gardens, Kew: Kew Publishing
  4. Hickey, M. & King, C. (2001), The Cambridge Illustrated Glossary of Botanical Terms, Cambridge University Press
  5. "Amphicarpous". Dictionary.com. Retrieved 2016-12-25.
  6. Swift, Joel F.; Smith, Stacy A.; Menges, Eric S.; Bassüner, Burgund; Edwards, Christine E. (2016-12-01). "Analysis of mating system and genetic structure in the endangered, amphicarpic plant, Lewton's polygala (Polygala lewtonii)". Conservation Genetics. 17 (6): 1269–1284. doi:10.1007/s10592-016-0860-3. ISSN 1566-0621.
  7. Herwig Teppner (2003), "The Heterodiaspory of Capsella bursa-pastoris (Brassicaceae)", Phyton, 43 (2): 381–391
  8. Weberling, Focko (1992). Morphology of Flowers and Inflorescences. CUP Archive. p. 345. ISBN 9780521438322.
  9. Ruiz de Clavijo, E. (1995). "The Ecological Significance of Fruit Heteromorphism in the Amphicarpic Species Catananche lutea (Asteraceae)". International Journal of Plant Sciences. 156 (6): 824–833. doi:10.1086/297306. JSTOR 2475114.
  10. Funk, Vicki A.; Fragman-Sapir, Ori (2009). "22. Gymnarrheneae (Gymnarrhenoideae)" (PDF). In V.A. Funk; A. Susanna; T. Stuessy; R. Bayer (eds.). Systematics, Evolution, and Biogeography of Compositae. Vienna: International Association for Plant Taxonomy. pp. 327–332. Retrieved 2016-12-27.
  11. Koller, Dov; Roth, Nurit (1964). "Studies on the Ecological and Physiological Significance of Amphicarpy in Gymnarrhena micrantha (Compositae)". American Journal of Botany. 51 (1): 26–35. doi:10.2307/2440059. JSTOR 2440059.
  12. U.S. Fish and Wildlife Service, Lewton's polygala (Polygala lewtonii), 5-Year Review: Summary and Evaluation (PDF), retrieved 2016-12-25
  13. Speroni, G.; Izaguirre, P.; Bernardello, G.; Franco, J. (2014). "Reproductive versatility in legumes: the case of amphicarpy in Trifolium polymorphum". Plant Biology. 16 (3): 690–6. doi:10.1111/plb.12113. PMID 24138122.
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