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The accumulation of genetic diversity within a canopy-stored seed bank.

Abstract

Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank.

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  • Publisher Full Text
  • Authors+Show Affiliations

    ,

    School of Biological Sciences, Institute for Conservation Biology, University of Wollongong, NSW 2522, Australia. dja@uow.edu.au

    , ,

    Source

    Molecular ecology 19:13 2010 Jul pg 2640-50

    MeSH

    Australia
    DNA, Plant
    Flowers
    Fruit
    Genetic Variation
    Genetics, Population
    Genotype
    Microsatellite Repeats
    Proteaceae
    Reproduction
    Seeds
    Sequence Analysis, DNA

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    20546132

    Citation

    TY - JOUR T1 - The accumulation of genetic diversity within a canopy-stored seed bank. AU - Ayre,David, AU - O'Brien,Eleanor, AU - Ottewell,Kym, AU - Whelan,Rob, Y1 - 2010/06/07/ PY - 2010/6/16/entrez PY - 2010/6/16/pubmed PY - 2010/9/21/medline SP - 2640 EP - 50 JF - Molecular ecology JO - Mol. Ecol. VL - 19 IS - 13 N2 - Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank. SN - 1365-294X UR - https://www.unboundmedicine.com/medline/citation/20546132/The_accumulation_of_genetic_diversity_within_a_canopy_stored_seed_bank_ L2 - http://dx.doi.org/10.1111/j.1365-294X.2010.04677.x ER -