The Origin of Isolating Mechanisms in Flowering Plants

Levin, Donald A.

doi:10.1007/978-1-4615-6956-5_4

Cited by 174 publications

(191 citation statements)

References 520 publications

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“…At this time the endosperm development stops, strongly indicating that seed abortion is caused by endosperm collapse. This phenomenon ("triploid block") is well known in inter-ploidy crosses (Levin 1978;Johnston et al, 1980;Pai-rot and Smith, 1986). The reason for abnormal endosperm development in inter-ploidy crosses is probably a deviation from the maternal : paternal genome ratio of 2: 1 in the endosperm ("endosperm balance number hypothesis", Johnston et a!., 1980).…”

Section: Mechanism Of Reproductive Isolationmentioning

confidence: 89%

Evidence for autotetraploidy in Plantago media and comparisons between natural and artificial cytotypes concerning cell size and fertility

Dijk

Delden

1990

Heredity

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The hypothesis of autotetraploidy in Plantago media (2n =12 and 2n = 24) was tested. The two cytotypes are morphologically very similar. Rare 4X and 3X hybrids were obtained in inter-ploidy crosses. The reproductive isolation between 2X and 4X is post-zygotic and can be broken down and introduced by colchicine treatment. The studied diploid and tetraploid populations shared the same alleles for nine allozyme loci. Together this provides strong evidence for autotetraploid origin of tetraploid P. media. Fertility of colchicine tetraploids was comparable to natural tetraploids and slightly lower than natural diploids. In contrast to colchicine tetraploids, natural tetraploids did not show gigascharacteristics. Tetraploid hybrids between diploids and natural tetraploids showed partial gigas-characteristics. The possible reasons for the differences in cell size between cytotypes are discussed. Differentiating characters between the natural cytotypes were not affected by colchicine treatment and are therefore not a direct consequence of polyploidization.

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Section: Mechanism Of Reproductive Isolationmentioning

confidence: 89%

Evidence for autotetraploidy in Plantago media and comparisons between natural and artificial cytotypes concerning cell size and fertility

Dijk

Delden

1990

Heredity

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“…Both observations would promote earlier flowering in S. vulgaris individuals produced from seeds that were shed in late summer and which germinated during early autumn. Although phenological separation is an important prezygotic isolating mechanism between related species (Levin, 1978(Levin, , 2000, it is probably only a contributing mechanism in the case of S. eboracensis and S. vulgaris as low levels of intertaxon crossing were recorded during periods when both species were flowering synchronously (May and June). Another factor that could significantly reduce the level of intertaxon crossing in the wild is conspecific clumping of S. vulgaris and S. eboracensis plants, which was recorded at the Dalton Terrace site.…”

Section: Discussionmentioning

confidence: 99%

Reproductive isolation of a new hybrid species, Senecio eboracensis Abbott & Lowe (Asteraceae)

Lowe

Abbott

2004

Heredity

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“…Questions that remain to be understood are how frequently hybridisation and introgression take place, and how these processes are modified by various ecological conditions. Several different barriers, both pre-and postzygotic, have the potential to reduce gene flow between species, eg, temporal divergence, gametic and zygotic incompatibility, hybrid inviability and sterility (Levin, 1978). If the paternity of B. rapa seeds.…”

Section: Introductionmentioning

confidence: 99%

Male fitness of oilseed rape (Brassica napus), weedy B. rapa and their F1 hybrids when pollinating B. rapa seeds

Pertl

Hauser

Damgaard³

et al. 2002

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The likelihood that two species hybridise and backcross may depend strongly on environmental conditions, and possibly on competitive interactions between parents and hybrids. We studied the paternity of seeds produced by weedy Brassica rapa growing in mixtures with oilseed rape (B. napus) and their F 1 hybrids at different frequencies and densities. Paternity was determined by the presence of a transgene, morphology, and AFLP markers. In addition, observations of flower and pollen production, and published data on pollen fertilisation success, zygote survival, and seed germination, allowed us to estimate an expected paternity. The frequency and density of B. napus, B. rapa, and F 1 plants had a strong influence on flower, pollen, and seed production, and on the

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The Origin of Isolating Mechanisms in Flowering Plants

Cited by 174 publications

References 520 publications

Evidence for autotetraploidy in Plantago media and comparisons between natural and artificial cytotypes concerning cell size and fertility

Evidence for autotetraploidy in Plantago media and comparisons between natural and artificial cytotypes concerning cell size and fertility

Reproductive isolation of a new hybrid species, Senecio eboracensis Abbott & Lowe (Asteraceae)

Male fitness of oilseed rape (Brassica napus), weedy B. rapa and their F1 hybrids when pollinating B. rapa seeds

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