Apomixis in the angiosperms

Nygren, Axel

doi:10.1007/978-3-642-95000-1_21

Cited by 42 publications

(37 citation statements)

References 241 publications

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“…Two species from this bee genus are known from the country, but both are rather rare and localised. Another way of long-term survival can be asexual seedproduction or vegetative reproduction, but the former is highly scarce (Nygren 1967) in European orchids.…”

Section: Resultsmentioning

confidence: 99%

An unexpected new record of the Mediterranean orchid, Ophrys bertolonii (Orchidaceae) in Central Europe

Molnár

Máté²,

Sramkó

2011

Biologia

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One flowering specimen of Ophrys bertolonii (s. str.) -a plant with a Circum-Adriatic distribution and hitherto unknown in other regions -was found on 7th May 2010 in the vicinity of Kunadacs (Central Hungary; N 47• 00 E 19• 17 ). The nearest known populations of this Mediterranean plant inhabit the Adriatic coast (ca. 450 km away) in Croatia, therefore this new occurrence represents a significant long distance dispersal event. The circumstances of the occurrence argue against introduction, but we can not decide now whether this new appearance is temporary or permanent. The permanent establishment of this strictly entomophilous plant requires the presence of its specific pollinator in the close neighbourhood of the habitat. However, no pollination was observed on the three flowers of the plant until 9th May, and one day later the stem had disappeared most likely due to grazing. Whatever the long-term fate of the plant is, this discovery represents a significant long distance (jump) dispersal event, and testifies to the dispersal ability of Ophrys species. Additionally, the appearance of a mature Adriatic plant in Central Europe fits well into the currently observed, climate change driven northward expansion of European orchids, therefore this finding most likely reflects a growing Mediterranean-like climatic influence in the region.

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Section: Resultsmentioning

confidence: 99%

An unexpected new record of the Mediterranean orchid, Ophrys bertolonii (Orchidaceae) in Central Europe

Molnár

Máté²,

Sramkó

2011

Biologia

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“…Another example that compilations may not be representative of the real incidence of the phenomenon in angiosperms is from the Anacardiaceae, Naumova (1993) Khokhlov (1976) states that 80 families and over 300 genera present apomixis. Tisserat et al (1979) updated the 37 families reported by Nygren (1954) and indicated 59 families and 138 genera. Naumova (1993) only tabulated adventitious embryony and registered 57 families, 121 genera, and 250 species.…”

Section: Resultsmentioning

confidence: 99%

Polyembryony in angiospermous trees of the Brazilian Cerrado and Caatinga vegetation

Salomão

Allem

2001

Acta Bot. Bras.

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-The occurrence of polyembryony was investigated in 75 woody species of the Cerrado in central Brazil and the xerophilous Caatinga vegetation in northeastern Brazil. Fourteen species showed polyembryony, a type of anomalous angiospermous reproduction. Polyembryony is reported for the first time for nine genera, Astronium, Byrsonima, Cariniana, Copaifera, Hancornia, Magonia, Myracrodruon, Tabebuia, and Tapirira. The positive correlation found between polyembryony, sexual reproduction, and apomictic processes suggests that a number of angiospermous species may make regular use of multiple breeding systems.Keywords -angiosperms, agamospermy, apomixis, polyembryony, Brazilian neotropics RESUMO -A ocorrência de poliembrionia foi investigada em 75 espécies lenhosas do Cerrado do Brasil central e da Caatinga xerófila do nordeste brasileiro. Quatorze espécies apresentaram poliembrionia, uma modalidade de reprodução anômala em angiospermas. Poliembrionia é relatada pela primeira vez para nove gêneros, Astronium, Byrsonima, Cariniana, Copaifera, Hancornia, Magonia, Myracrodruon, Tabebuia e Tapirira. A correlação positiva encontrada entre poliembrionia, reprodução sexual e processos apomíticos sugere que parte das espécies de angiospermas faça uso regular de sistemas de cruzamento múltiplos.Palavras-chave -angiospermas, agamospermia, apomixia, poliembrionia, neotrópico brasileiro Recebido em 29/09/00. Aceito em 25/07/01.

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“…Reproduction in A. holboellii may be sexual or apomictic (Bacher, 1947(Bacher, , 1951(Bacher, , 1969Nygren, 1954). I have verified, by emasculation and crossing experiments (Roy, 1992;unpubl.…”

Section: The Hostsmentioning

confidence: 88%

PATTERNS OF RUST INFECTION AS A FUNCTION OF HOST GENETIC DIVERSITY AND HOST DENSITY IN NATURAL POPULATIONS OF THE APOMICTIC CRUCIFER, ARABIS HOLBOELLII

Roy

1993

Evolution

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Abstract.-It is often assumed that genetic diversity contributes to reduced disease incidence in natural plant populations. However, little is known about the genetic structure of natural populations affected by disease. Here I present data from three apomictic (asexual) populations ofArabis holboellii infected by the rusts Puccinia monoica and P. thlaspeos. An average of300 host individuals per population were genotyped (using seven variable allozyme loci) and scored for disease presence. Arabis holboellii populations are genetically diverse; the number of clones detected per population ranged from 6 to 27. There was substantial variation in frequency of host clones within and among sites, and significant variation among clones in susceptibility to the different rusts. Contrary to predictions based on frequency-dependent selection theory there was not a consistent positive relationship between clone frequency and disease incidence within any of the populations (Spearman's r = -0.096, P > 0.5). In addition, cionally diverse populations did not necessarily have decreased disease incidence. The population with the lowest overall (both pathogens combined) disease incidence (7.5 ± 1.9%) had the smallest number ofclones (6), the lowest spatial variability, and the highest Arabis density. By comparison, another population had 22 clones, high spatial variability, low Arabis density and significantly more disease overall (16.8 ± 2.7%). Although this study does not eliminate the possibility of frequency-dependent pathogen attack in these populations, the results suggest that it is likely to be weak or intermittent.

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Apomixis in the angiosperms

Cited by 42 publications

References 241 publications

An unexpected new record of the Mediterranean orchid, Ophrys bertolonii (Orchidaceae) in Central Europe

An unexpected new record of the Mediterranean orchid, Ophrys bertolonii (Orchidaceae) in Central Europe

Polyembryony in angiospermous trees of the Brazilian Cerrado and Caatinga vegetation

PATTERNS OF RUST INFECTION AS A FUNCTION OF HOST GENETIC DIVERSITY AND HOST DENSITY IN NATURAL POPULATIONS OF THE APOMICTIC CRUCIFER, ARABIS HOLBOELLII

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