Geitonogamy
Geitonogamy (from Greek geiton (γείτων) = neighbor + gamein (γαμεῖν) = to marry) is a type of self-pollination.[1] Geitonogamous pollination is sometimes distinguished from the fertilizations that can result from it, geitonogamy.[2] If a plant is self-incompatible, geitonogamy can reduce seed production.[3]
In flowering plants, pollen is transferred from a flower to another flower on the same plant, and in animal pollinated systems this is accomplished by a pollinator visiting multiple flowers on the same plant. Geitonogamy is also possible within species that are wind-pollinated, and may actually be a quite common source of self-fertilized seeds in self-compatible species.[4] It also occurs in monoecious gymnosperms.[5]
Empirical work shows that geitonogamy is seldom a marginal process: in many flowering plants it represents a sizeable share of all pollen transfer and its incidence rises steeply as the number of simultaneously open flowers on a plant increases. Field experiments and pollen-movement models indicate that a plant with ten open flowers may experience about 13% geitonogamous pollen receipt, whereas a display of fifty flowers can push that figure beyond 45%; at the same time, pollen export per flower drops sharply as self-delivery soaks up the grains that would otherwise reach neighbouring individuals.[6]
Because pollen retained within the parent plant earns little or no male fitness and may interfere with female success, geitonogamy carries measurable costs. In self-incompatible species experimental precedence of self-pollen has reduced subsequent seed set by up to 40%, whereas in self-compatible taxa any level of inbreeding depression means that seeds sired through geitonogamy are, on average, less fit than outcrossed progeny. These effects are especially pronounced in large, many-flowered clones, helping to explain selection for traits—such as staggered flowering, directional nectar gradients or architectural arrangements that guide pollinators away from older female-phase flowers—that reduce successive visits to blossoms on the same individual.[6]
See also
[edit]References
[edit]- ^ Eckert, C.G. (2000). "Contributions of autogamy and geitonogamy to self-fertilization in a mass-flowering, clonal plant". Ecology. 81 (2): 532–542. doi:10.1890/0012-9658(2000)081[0532:coaagt]2.0.co;2.
- ^ Hessing, M.B. (1988). "Geitonogamous Pollination and Its Consequences in Gernium caespitosum". American Journal of Botany. 75 (9): 1324–1333. doi:10.2307/2444455. JSTOR 2444455.
- ^ Ito, E.; Kikuzawa, K. (2003), "Reduction of geitonogamy: Flower abscission for departure of pollinators", Ecological Research, 18 (2): 177–183, doi:10.1046/j.1440-1703.2003.00545.x, S2CID 22698719
- ^ Friedman, J.; Barrett, S.C.H. (January 2009). "The consequences of monoecy and protogyny for mating in wind-pollinated Carex". New Phytologist. 181 (2): 489–497. CiteSeerX 10.1.1.708.6664. doi:10.1111/j.1469-8137.2008.02664.x. PMID 19121043.
- ^ Williams, C.G. (2009). Conifer Reproductive Biology. New York: Springer. ISBN 9781402096013. OCLC 405547163.
- ^ a b de Jong, Tom J.; Waser, Nickolas M.; Klinkhamer, Peter G.L. (1993). "Geitonogamy: the neglected side of selfing". Trends in Ecology & Evolution. 8 (9): 321–325. doi:10.1016/0169-5347(93)90239-L.