Comparison of gemma production among three Lophozia species during the growing season

Holá, Eva; Kučera, Jan; Těšitel, Jakub

doi:10.1016/j.flora.2011.04.005

Cited by 2 publications

(3 citation statements)

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“…Shoot-level production of gemmae, on the other hand, falling mostly in the range 900-5000 per shoot, is broadly in keeping with previous reports of 1000-7000 for Lophozia silvicola, and a mean of 1181 for Anastrophyllum hellerianum (Laaka-Lindberg, 1999;Pohjamo & Laaka-Lindberg, 2003, 2004. Holá et al (2011) examined gemma production in three Lophozia species including L. ventricosa, but comparison with our study is difficult since they provide no summary statistics and furthermore included non-gemmiferous shoots in their reported output. Their study, however, provides evidence of seasonality in gemma production that varies across species.…”

Section: Discussionsupporting

confidence: 90%

“…Despite the obvious importance of asexual propagules, studies quantifying their production, and its relationship to other demographic and populationecological variables, remain uncommon (Sö derströ m, 1994;Laaka-Lindberg, 1999;Holá et al, 2011). A simple model relating various population features to gemma output per colony is summarized in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

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Gemma output in the liverwortLophozia ventricosa(Dicks.) Dumort: spatial variation, density dependence, and relationships among production components

Algar-Hedderson

Söderström

Hedderson

2013

Journal of Bryology

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Although gemma production is common among liverworts, and thought to play a key role in their population dynamics, quantitative data on numbers produced at shoot and colony levels, or on spatial variation in these numbers, are very sparse. Here we investigate gemma output of a boreal and arctic liverwort species, Lophozia ventricosa, at populations in Trøndelag, a boreal region of central Norway, and in arctic tundra on Svalbard. Production parameters investigated include colony size, shoot density, number of gemmae per shoot, proportion of shoots gemmiferous, and gemmiferous shoot density. Colony-level output was calculated as the product of the number of gemmae per shoot, colony size, and gemmiferous shoot density. Nested analysis of variance, used to spatially partition variance in these gemma-production components, reveals that the vast majority of the variation lies at the measurement level, i.e. among shoots within colonies or among colonies within plots. The only significant difference between the two geographic areas is that in boreal sites shoots tend to produce slightly more gemmae, and form larger, denser, colonies. This translates to somewhat higher colony-level output in boreal, compared to arctic, sites. Evaluation of a structural equations model reveals intricate patterns of relationship among the production components and provides strong evidence of negative density dependence of shoot-level production. We argue that explicit evaluation of size-number tradeoffs, allometric scaling of production with shoot size, and detailed studies of genetic versus phenotypic effects on production levels, are necessary to understand how asexual propagule production is shaped by selection on life histories.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Gemma output in the liverwortLophozia ventricosa(Dicks.) Dumort: spatial variation, density dependence, and relationships among production components

Algar-Hedderson

Söderström

Hedderson

2013

Journal of Bryology

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“…A drop of detergent (0.5% Triton X‐100, Gerbu) was added to the sample prior to microscopy to reduce the surface tension. The gemma counting for each sample was repeated three times (see Holá, Kučera & Těšitel, ). In addition, the length of the main stems, branches and entire shoots, shoot and branch type, number of branches and the branching pattern of shoots were assessed to describe the shoot architecture of individuals of the gemmiparous S. undulata shoots.…”

Section: Methodsmentioning

confidence: 99%

Sex ratio, sex-specific pattern in vegetative growth and gemma production in an aquatic liverwort,Scapania undulata(Marchantiophyta: Scapaniaceae)

et al. 2014

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Scapania undulata is an aquatic dioicous liverwort growing in shallow streams in boreal to subtropical zones. We studied the expressed sex ratio, sex-specific differences in shoot architecture and possible trade-off between sexual and asexual reproduction in ten populations of S. undulata by surveying 100 plots in ten streams in southern Finland. The expressed sex ratio was male biased, in contrast with the sex ratio in most dioicous bryophytes. It was also highly variable between the streams, but individual plots frequently comprised shoots from only one sex. The overproduction of males might be a strategy to overcome sperm dilution and ensure fertilization over longer distances in water. No size differences between females and males were detected, but they differed in branching patterns. Evidence for a higher cost of sexual reproduction in females than males can be seen from the following: the male-biased sex ratio; low number of sex-expressing female shoots in female-only plots; no co-occurrence of gemmae and female sex organs on a single branch, and no more than one sexual branch per female shoot. In contrast, high gemma production of male and female sex-expressing shoots indicates a minimal trade-off between sexual and asexual reproduction.

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Comparison of gemma production among three Lophozia species during the growing season

Cited by 2 publications

References 27 publications

Gemma output in the liverwortLophozia ventricosa(Dicks.) Dumort: spatial variation, density dependence, and relationships among production components

Gemma output in the liverwortLophozia ventricosa(Dicks.) Dumort: spatial variation, density dependence, and relationships among production components

Sex ratio, sex-specific pattern in vegetative growth and gemma production in an aquatic liverwort,Scapania undulata(Marchantiophyta: Scapaniaceae)

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