Apomixis in the angiosperms. II

Nygren, Axel

doi:10.1007/bf02958805

Cited by 94 publications

(36 citation statements)

References 161 publications

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“…Aparentemente, as espécies agamospérmicas tropicais diferem das de clima temperado quanto aos mecanismos empregados na reprodução assexuada: enquanto que as primeiras costumam apresentar embrionia adventícia, nas demais são mais freqüentes mecanismos como aposporia e diplosporia (Baker et al 1982). Entre espécies tropicais, a apomixia foi encontrada em Poaceae (Carneiro & Dusi 2002), Dipterocarpaceae (Kaur et al 1978), Melastomataceae (Renner 1989, Goldenberg & Shepherd 1998, Bombacaceae (Oliveira et al 1992), Clusiaceae (Ha et al 1988), Erythroxylaceae (Berry et al 1991), além de Amaryllidaceae, Anacardiaceae, Araceae, Cactaceae, Euphorbiaceae, Gentianaceae, Myrtaceae e Orchidaceae (Nygren 1954). Várias espécies de cerrado apresentam poliembrionia, que pode estar relacionada à apomixia (Salomão & Allem 2001).…”

Section: Introductionunclassified

Ocorrência de apomixia e partenocarpia em algumas espécies subtropicais de Asteraceae

Werpachowski¹,

Varassin²,

Goldenberg³

2004

Rev. bras. Bot.

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Section: Introductionunclassified

Ocorrência de apomixia e partenocarpia em algumas espécies subtropicais de Asteraceae

Werpachowski¹,

Varassin²,

Goldenberg³

2004

Rev. bras. Bot.

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“…Since then, some 250 species belonging to 22 families have been found to reproduce wholly or partly by agamospermy via a variety of embryological pathways (reviews in Nygren, 1954Nygren, , 1967Battagalia, 1963;Grant, 1971).…”

Section: Introductionmentioning

confidence: 99%

“…Further, past studies indicate that agamospermous species are usually perennial and derived from strongly outcrossing ancestors. They also show that agamospermy is often, but by no means invariably, associated with interspecific hybridization and polyploidy (Gustafsson, 1946(Gustafsson, , 1947aStebbins, 1950;Nygren, 1954Nygren, , 1967Knox, 1967;Knox and Heslop-Harrison, 1963;Grant, 1971).…”

Section: Introductionmentioning

confidence: 99%

The evolution of apomixis

Marshall

Brown

1981

Heredity

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SUMMARYThe selective forces responsible for the evolution of gametophytic apomixis in outbreeding plant populations are analysed in terms of a simple single gene model. In the absence of selection, apomixis inevitably becomes fixed in a population. This conclusion holds regardless of the dominance relations of the alleles specifying apomictic versus sexual seed formation. Substantial heterotic viability selection is required to prevent fixation of recessive and codominant apomictic alleles and maintain a stable polymorphism at the mating system locus. These findings suggest that gametophytic apomixis should be a common mode of reproduction in plant species. Possible factors accounting for the relative paucity of apomictic plants are discussed. It is concluded that one of the major factors hindering the spread of apomixis is its usually complex inheritance and the need to accumulate, in the one individual, two or more mutations affecting meiosis and the reproductive system.

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“…These data indicate that perfect flowers are dependent on the pollination (selfing or crossing) for the seed production. (Nygren, 1954), and Atraphaxis frutescens (L.) Eversm. (Asker and Jerling, 1992).…”

Section: Resultsmentioning

confidence: 99%