Labile sex expression in plants

Korpelainen, Helena

doi:10.1111/j.1469-185x.1997.tb00028.x

Cited by 96 publications

(112 citation statements)

References 182 publications

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“…In many plant species, sex expression varies within individuals in relation to resource status, although such variation is not ubiquitous (reviewed in Korpelainen 1998). For masting species, if seed dispersal and survival are higher in mast years, fitness is an accelerating function of investment in female reproductive function (Charnov 1979).…”

Section: Discussionmentioning

confidence: 99%

Sex allocation, pollen limitation and masting in whitebark pine

2013

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Summary1. Masting, the synchronous and episodic production of seed crops, is thought to benefit plant reproductive success through positive density-dependent effects on pollination, dispersal and seed survival. Of these, only increased pollination efficiency in mast years can be a proximate mechanism for masting by synchronizing reproductive effort across individuals through pollen coupling. 2. Increased pollination efficiency requires synchronous investment in male and female function during mast years. Sex allocation theory, however, predicts a trade-off in investment between male and female reproductive allocation dependent on total resources invested in reproduction. 3. We describe patterns of sex allocation in Pinus albicaulis (whitebark pine), using data on pollen and seed cone counts over 5 years for 29 trees across 7 sites in Montana, U.S.A. 4. Whitebark pine seed cone maturation increased with site pollen cone production, indicating pollen limitation, and pollen and seed cone production were positively correlated across years. 5. Simulating mature seed cone production from these empirical relationships resulted in greater average mature seed cone production than alternative scenarios of (i) no synchrony between pollen cone production and pollen cone initiation, (ii) negative correlation (trade-off) between seed cone initiation and pollen cone production or (iii) no masting. 6. Synthesis. Our data support a role for pollination efficiency in both increasing long-term seed production and as a proximate mechanism for synchronizing masting in Pinus albicaulis. Increased pollination efficiency joins greater seed dispersal and survival in mast years seen in other studies, as an additional positive density-dependent benefit of masting. Positive density-dependent fitness benefits may therefore influence patterns of sex allocation in relation to total resources invested in reproduction. The pollen limitation found here combined with stand isolation and reduced tree density due to mortality from forest pests and other environmental stressors may lead to reduced seed cone maturation and changes in masting patterns.

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Section: Discussionmentioning

confidence: 99%

Sex allocation, pollen limitation and masting in whitebark pine

2013

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“…Fully environmental s.d. is known for several homosporous ferns, where sex expression of gametophytes depends on interplant signalling through hormone release and perception (Banks, 1994(Banks, , 1997Korpelainen, 1998;Desoto et al, 2008). Most plants with separate sexes, however, appear to possess genetic s.d., with either heteromorphic or homomorphic sex chromosomes (Ming et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Sex determination in dioecious Mercurialis annua and its close diploid and polyploid relatives

Russell

Pannell

2014

Heredity

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Separate sexes have evolved on numerous independent occasions from hermaphroditic ancestors in flowering plants. The mechanisms of sex determination is known for only a handful of such species, but, in those that have been investigated, it usually involves alleles segregating at a single locus, sometimes on heteromorphic sex chromosomes. In the genus Mercurialis, transitions between combined (hermaphroditism) and separate sexes (dioecy or androdioecy, where males co-occur with hermaphrodites rather than females) have occurred more than once in association with hybridisation and shifts in ploidy. Previous work has pointed to an unusual 3-locus system of sex determination in dioecious populations. Here, we use crosses and genotyping for a sex-linked marker to reject this model: sex in diploid dioecious M. annua is determined at a single locus with a dominant male-determining allele (an XY system). We also crossed individuals among lineages of Mercurialis that differ in their ploidy and sexual system to ascertain the extent to which the same sex-determination system has been conserved following genome duplication, hybridisation and transitions between dioecy and hermaphroditism. Our results indicate that the maledetermining element is fully capable of determining gender in the progeny of hybrids between different lineages. Specifically, males crossed with females or hermaphrodites always generate 1:1 male:female or male:hermaphrodite sex ratios, respectively, regardless of the ploidy levels involved (diploid, tetraploid or hexaploid). Our results throw further light on the genetics of the remarkable variation in sexual systems in the genus Mercurialis. They also illustrate the almost identical expression of sexdetermining alleles in terms of sexual phenotypes across multiple divergent backgrounds, including those that have lost separate sexes altogether.

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“…Accordingly, sex changes with increased size (Bierzychudek 1982) or age (Lloyd and Bawa 1984) have been demonstrated. Second, several environmental conditions have been reported to be responsible for switching sex (reviewed in Korpelainen 1998). Sex changes in plants have been considered as a strategy of sex allocation to enhance fitness over the lifetime of plants (Freeman et al 1980;Policansky 1981;Lloyd and Bawa 1984).…”

Section: Discussionmentioning

confidence: 99%

“…Individuals of a large number of dioecious species are able to change their sexual expression showing sex lability (reviewed in Freeman et al 1980;Korpelainen 1998) and this may cause biased sex ratios (vi). Two mutually not exclusive explanations have been proposed to explain sex lability.…”

Section: Discussionmentioning

confidence: 99%

“…The mechanisms leading to SSS include sexassociated differential germination (Eppley 2001), differential mortality of males and females in different sites (e.g. Meagher and Antonovics 1982;Gibson and Menges 1994), the ability to switch sex based on the environmental conditions (reviewed in Korpelainen 1998), and the different use of resources by the two sexes Obeso 2002). …”

Section: Introductionmentioning

confidence: 99%

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Sex ratio and spatial distribution of male and female Antennaria dioica (Asteraceae) plants

Varga

Kytöviita

2011

Acta Oecologica

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Sex ratio, sex spatial distribution and sexual dimorphism in reproduction and arbuscular mycorrhizal colonisation were investigated in the dioecious clonal plant Antennaria dioica (Asteraceae). Plants were monitored for five consecutive years in six study plots in Oulanka, northern Finland. Sex ratio, spatial distribution of sexes, flowering frequency, number of floral shoots and the number and weight of inflorescences were recorded. In addition, intensity of mycorrhizal fungi in the roots was assessed. Both sexes flowered each year with a similar frequency, but the overall genet sex ratio was strongly female-biased. The bivariate Ripley's analysis of the sex distribution showed that within most plots sexes were randomly distributed except for one plot. Sexual dimorphism was expressed as larger floral and inflorescence production and heavier inflorescences in males. In addition, the roots of both sexes were colonised to a similar extent by arbuscular mycorrhizal fungi. The female sex-biased flowering ratios reported are not consistent among years and cannot be explained in terms of spatial segregation of the sexes or sex lability. The possible reasons for the female-biased sex ratio are discussed.

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Labile sex expression in plants

Cited by 96 publications

References 182 publications

Sex allocation, pollen limitation and masting in whitebark pine

Sex allocation, pollen limitation and masting in whitebark pine

Sex determination in dioecious Mercurialis annua and its close diploid and polyploid relatives

Sex ratio and spatial distribution of male and female Antennaria dioica (Asteraceae) plants

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