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Volumn 103, Issue 9, 2009, Pages 1385-1394

Flowering phenology influences seed production and outcrossing rate in populations of an alpine snowbed shrub, Phyllodoce aleutica: Effects of pollinators and self-incompatibility

Author keywords

Alpine snowbed; autogamy; bumble bee; cryptic self incompatibility; flowering phenology; mixed pollination; outcrossing rate; Phyllodoce aleutica; pollination success; seasonality; self pollination

Indexed keywords

BOMBUS (GENUS); PHYLLODOCE ALEUTICA;

EID: 67650725981     PISSN: 03057364     EISSN: 10958290     Source Type: Journal    
DOI: 10.1093/aob/mcp037     Document Type: Article
Times cited : (56)

References (52)
  • 1
    • 0035135771 scopus 로고    scopus 로고
    • Flower sex ratio, pollinator abundance, and the seasonal pollination dynamics of a protandrous plant
    • Aizen MA. 2001. Flower sex ratio, pollinator abundance, and the seasonal pollination dynamics of a protandrous plant. Ecology 82: 127-144.
    • (2001) Ecology , vol.82 , pp. 127-144
    • Aizen, M.A.1
  • 2
    • 15244355120 scopus 로고    scopus 로고
    • Interspecific competition for pollination lowers seed production and outcrossing in Mimulus ringens
    • Bell JM, Karron JD, Mitchell RJ. 2005. Interspecific competition for pollination lowers seed production and outcrossing in Mimulus ringens. Ecology 86: 762-771.
    • (2005) Ecology , vol.86 , pp. 762-771
    • Bell, J.M.1    Karron, J.D.2    Mitchell, R.J.3
  • 3
    • 84995108066 scopus 로고
    • Variation in outcrossing rates in Eichhornia paniculata: The role of demographic and reproductive factors
    • Barrett SCH, Husband B. 1990. Variation in outcrossing rates in Eichhornia paniculata: the role of demographic and reproductive factors. Plant Species Biology 5: 41-55.
    • (1990) Plant Species Biology , vol.5 , pp. 41-55
    • Barrett, S.C.H.1    Husband, B.2
  • 4
    • 0013389539 scopus 로고    scopus 로고
    • Competition for pollination between an invasive species (purple loosestrife) and a native congener
    • Brown BJ, Mitchell RJ, Graham SA. 2002. Competition for pollination between an invasive species (purple loosestrife) and a native congener. Ecology 83: 2328-2336.
    • (2002) Ecology , vol.83 , pp. 2328-2336
    • Brown, B.J.1    Mitchell, R.J.2    Graham, S.A.3
  • 5
    • 33646825814 scopus 로고    scopus 로고
    • Impact of insect pollinator group and floral display size on outcrossing rate
    • Brunet J, Sweet HR. 2006. Impact of insect pollinator group and floral display size on outcrossing rate. Evolution 60: 234-246.
    • (2006) Evolution , vol.60 , pp. 234-246
    • Brunet, J.1    Sweet, H.R.2
  • 6
    • 0027804747 scopus 로고
    • Contribution of cryptic incompatibility to the mating system of Eichhornia paniculata (Pontederiaceae)
    • Cruzan MB, Barrett SCH. 1993. Contribution of cryptic incompatibility to the mating system of Eichhornia paniculata (Pontederiaceae). Evolution 47: 925-934.
    • (1993) Evolution , vol.47 , pp. 925-934
    • Cruzan, M.B.1    Barrett, S.C.H.2
  • 7
    • 0033918412 scopus 로고    scopus 로고
    • Contributions of autogamy and geitonogamy to selffertilization in a mass-flowering, clonal plant
    • Eckert CG. 2000. Contributions of autogamy and geitonogamy to selffertilization in a mass-flowering, clonal plant. Ecology 81: 532-542.
    • (2000) Ecology , vol.81 , pp. 532-542
    • Eckert, C.G.1
  • 8
    • 0028164302 scopus 로고
    • Post-pollination mechanisms and the maintenance of outcrossing in self-compatible, tristylous, Decodon verticillatus (Lythraceae)
    • Eckert CG, Barrett SCH. 1994. Post-pollination mechanisms and the maintenance of outcrossing in self-compatible, tristylous, Decodon verticillatus (Lythraceae). Heredity 72: 396-411.
    • (1994) Heredity , vol.72 , pp. 396-411
    • Eckert, C.G.1    Barrett, S.C.H.2
  • 9
    • 0038035464 scopus 로고    scopus 로고
    • Outcrossing rate and inbreeding depression in the herbaceous autotetrapoid, Campanula americana
    • Galloway LF, Etterson JR, Hamrick JL. 2003. Outcrossing rate and inbreeding depression in the herbaceous autotetrapoid, Campanula americana. Heredity 90: 308-315.
    • (2003) Heredity , vol.90 , pp. 308-315
    • Galloway, L.F.1    Etterson, J.R.2    Hamrick, J.L.3
  • 10
    • 0034496786 scopus 로고    scopus 로고
    • Why do pollinators visit proportionally fewer flowers in large patches
    • Goulson D. 2000. Why do pollinators visit proportionally fewer flowers in large patches? Oikos 91: 485-492.
    • (2000) Oikos , vol.91 , pp. 485-492
    • Goulson, D.1
  • 11
    • 0037149477 scopus 로고    scopus 로고
    • Genetic cost of reproductive assurance in a self-fertilizing plant
    • Herlihy CR, Eckert CG. 2002. Genetic cost of reproductive assurance in a self-fertilizing plant. Nature 416: 320-323.
    • (2002) Nature , vol.416 , pp. 320-323
    • Herlihy, C.R.1    Eckert, C.G.2
  • 12
    • 16244398687 scopus 로고    scopus 로고
    • Evolution of self-fertilization at geographical range margins? A comparison of demographic, floral, and mating system variables in central vs peripheral populations of Aquilegia canadensis (Ranunculaceae)
    • Herlihy CR, Eckert CG. 2005. Evolution of self-fertilization at geographical range margins? A comparison of demographic, floral, and mating system variables in central vs. peripheral populations of Aquilegia canadensis (Ranunculaceae). American Journal of Botany 92: 744-751.
    • (2005) American Journal of Botany , vol.92 , pp. 744-751
    • Herlihy, C.R.1    Eckert, C.G.2
  • 13
    • 33645028799 scopus 로고    scopus 로고
    • Seasonal changes in pollinator activity influence pollen dispersal and seed production of the alpine shrub Rhododendron aureum (Ericaceae)
    • Hirao AS, Kameyama Y, Ohara M, Isagi Y, Kudo G. 2006. Seasonal changes in pollinator activity influence pollen dispersal and seed production of the alpine shrub Rhododendron aureum (Ericaceae). Molecular Ecology 15: 1165-1173.
    • (2006) Molecular Ecology , vol.15 , pp. 1165-1173
    • Hirao, A.S.1    Kameyama, Y.2    Ohara, M.3    Isagi, Y.4    Kudo, G.5
  • 14
    • 0033679240 scopus 로고    scopus 로고
    • Early-acting inbreeding depression in three species of Vaccinium (Ericaceae)
    • Hokanson K, Hancock J. 2000. Early-acting inbreeding depression in three species of Vaccinium (Ericaceae). Sexual Plant Reproduction 13: 145-150.
    • (2000) Sexual Plant Reproduction , vol.13 , pp. 145-150
    • Hokanson, K.1    Hancock, J.2
  • 15
    • 0024248605 scopus 로고
    • Pollination biology in the Snowy Mountains of Australia: Comparisons with montane Colorado, USA
    • Inouye DW, Pyke GH. 1988. Pollination biology in the Snowy Mountains of Australia: comparisons with montane Colorado, USA. Australian Journal of Ecology 13: 191-210.
    • (1988) Australian Journal of Ecology , vol.13 , pp. 191-210
    • Inouye, D.W.1    Pyke, G.H.2
  • 16
    • 33645243584 scopus 로고    scopus 로고
    • Maintenance of inbreeding depression in a highly selffertilizing tree, Magnolia obovata Thunb
    • Ishida K. 2006. Maintenance of inbreeding depression in a highly selffertilizing tree, Magnolia obovata Thunb. Evolutionary Ecology 20: 173-191.
    • (2006) Evolutionary Ecology , vol.20 , pp. 173-191
    • Ishida, K.1
  • 18
    • 1342330829 scopus 로고    scopus 로고
    • Benefits of autonomous selfing under unpredictable pollinator environments
    • Kalisz S, Vogler DW. 2003. Benefits of autonomous selfing under unpredictable pollinator environments. Ecology 84: 2928-2942.
    • (2003) Ecology , vol.84 , pp. 2928-2942
    • Kalisz, S.1    Vogler, D.W.2
  • 19
    • 33646869288 scopus 로고    scopus 로고
    • Eight microsatellite markers for sympatric alpine shrubs, Phyllodoce aleutica and P caerulea (Ericaceae)
    • Kameyama Y, Kasagi T, Kudo G. 2006. Eight microsatellite markers for sympatric alpine shrubs, Phyllodoce aleutica and P. caerulea (Ericaceae). Molecular Ecology Notes 6: 402-404.
    • (2006) Molecular Ecology Notes , vol.6 , pp. 402-404
    • Kameyama, Y.1    Kasagi, T.2    Kudo, G.3
  • 20
    • 38849190543 scopus 로고    scopus 로고
    • A hybrid zone dominated by fertile F1s of two alpine shrub species, Phyllodoce caerulea and Phyllodoce aleutica, along a snowmelt gradient
    • Kameyama Y, Kasagi T, Kudo G. 2008. A hybrid zone dominated by fertile F1s of two alpine shrub species, Phyllodoce caerulea and Phyllodoce aleutica, along a snowmelt gradient. Journal of Evolutionary Biology 21: 588-597.
    • (2008) Journal of Evolutionary Biology , vol.21 , pp. 588-597
    • Kameyama, Y.1    Kasagi, T.2    Kudo, G.3
  • 21
    • 0036966649 scopus 로고    scopus 로고
    • Intraspecific variations in selfing ability of two sympatric alpine shrubs, Phyllodoce caerulea and Phyllodoce aleutica, along snowmelt gradients
    • Kasagi T. 2002. Intraspecific variations in selfing ability of two sympatric alpine shrubs, Phyllodoce caerulea and Phyllodoce aleutica, along snowmelt gradients. Plant Species Biology 17: 133-138.
    • (2002) Plant Species Biology , vol.17 , pp. 133-138
    • Kasagi, T.1
  • 22
    • 0348196943 scopus 로고    scopus 로고
    • Variations in bumble bee preference and pollen limitation among neighboring populations: Comparisons between Phyllodoce caerulea and Phyllodoce aleutica (Ericaceae) along snowmelt gradients
    • Kasagi T, Kudo G. 2003. Variations in bumble bee preference and pollen limitation among neighboring populations: comparisons between Phyllodoce caerulea and Phyllodoce aleutica (Ericaceae) along snowmelt gradients. American Journal of Botany 90: 1321-1327.
    • (2003) American Journal of Botany , vol.90 , pp. 1321-1327
    • Kasagi, T.1    Kudo, G.2
  • 23
    • 14844342446 scopus 로고    scopus 로고
    • Interspecific pollinator movements and heterospecific incompatibility: Comparisons between Phyllodoce caerulea and Phyllodoce aleutica along snowmelt gradients
    • Kasagi T, Kudo G. 2005. Interspecific pollinator movements and heterospecific incompatibility: comparisons between Phyllodoce caerulea and Phyllodoce aleutica along snowmelt gradients. Evolutionary Ecology Research 7: 73-87.
    • (2005) Evolutionary Ecology Research , vol.7 , pp. 73-87
    • Kasagi, T.1    Kudo, G.2
  • 24
    • 0001553950 scopus 로고
    • Embryonic genetic load in the highbush blueberry, Vaccinium corymbosum (Ericaceae)
    • Krebs SL, Hancock JF. 1991. Embryonic genetic load in the highbush blueberry, Vaccinium corymbosum (Ericaceae). American Journal of Botany 78: 1427-1437.
    • (1991) American Journal of Botany , vol.78 , pp. 1427-1437
    • Krebs, S.L.1    Hancock, J.F.2
  • 25
    • 43049092654 scopus 로고    scopus 로고
    • Adaptive significance of self-fertilization in a hermaphroditic perennial, Trillium camshatcense (Melanthiaceae)
    • Kubota S, Kameyama Y, Hirao AS, Ohara M. 2008. Adaptive significance of self-fertilization in a hermaphroditic perennial, Trillium camshatcense (Melanthiaceae). American Journal of Botany 95: 482-489.
    • (2008) American Journal of Botany , vol.95 , pp. 482-489
    • Kubota, S.1    Kameyama, Y.2    Hirao, A.S.3    Ohara, M.4
  • 26
    • 0026314192 scopus 로고
    • Effects of snows-free period on the phenology of alpine plants inhabiting snow patches
    • Kudo G. 1991. Effects of snows-free period on the phenology of alpine plants inhabiting snow patches. Arctic and Alpine Research 23: 436-443.
    • (1991) Arctic and Alpine Research , vol.23 , pp. 436-443
    • Kudo, G.1
  • 27
    • 0027332997 scopus 로고
    • Relationship between flowering time and fruit set of the entomophilous alpine shrub, Rhododendron aureum (Ericaceae), inhabiting snow patches
    • Kudo G. 1993. Relationship between flowering time and fruit set of the entomophilous alpine shrub, Rhododendron aureum (Ericaceae), inhabiting snow patches. American Journal of Botany 80: 1300-1304.
    • (1993) American Journal of Botany , vol.80 , pp. 1300-1304
    • Kudo, G.1
  • 28
    • 44649127641 scopus 로고    scopus 로고
    • Flowering phenologies of animal-pollinated plants: Reproductive strategies and agents of selection
    • Barrett SCH, Harder LDeds. Oxford; Oxford University Press
    • Kudo G. 2006. Flowering phenologies of animal-pollinated plants: reproductive strategies and agents of selection. In: Barrett SCH, Harder LDeds. Ecology and evolution of flowers. Oxford; Oxford University Press, 139-155.
    • (2006) Ecology and Evolution of Flowers , pp. 139-155
    • Kudo, G.1
  • 29
    • 31544434554 scopus 로고    scopus 로고
    • Habitat-specific responses in the flowering phenology and seed set of alpine plants to climate variation: Implications for global-change impacts
    • Kudo G, Hirao AS. 2006. Habitat-specific responses in the flowering phenology and seed set of alpine plants to climate variation: implications for global-change impacts. Population Ecology 48: 49-58.
    • (2006) Population Ecology , vol.48 , pp. 49-58
    • Kudo, G.1    Hirao, A.S.2
  • 30
    • 11144258290 scopus 로고    scopus 로고
    • Flowering phenology of alpine plant communities along a gradient of snowmelt timing
    • Kudo G, Suzuki S. 1999. Flowering phenology of alpine plant communities along a gradient of snowmelt timing. Polar Bioscience 12: 100-113.
    • (1999) Polar Bioscience , vol.12 , pp. 100-113
    • Kudo, G.1    Suzuki, S.2
  • 31
    • 0036280877 scopus 로고    scopus 로고
    • Relationships between flowering phenology and fruit-set of dwarf shrubs in alpine fellfields in northern Japan: A comparison with a subarctic heath land in northern Sweden
    • Kudo G, Suzuki S. 2002. Relationships between flowering phenology and fruit-set of dwarf shrubs in alpine fellfields in northern Japan: A comparison with a subarctic heath land in northern Sweden. Arctic, Antarctic, and Alpine Research 34: 185-190.
    • (2002) Arctic, Antarctic, and Alpine Research , vol.34 , pp. 185-190
    • Kudo, G.1    Suzuki, S.2
  • 32
    • 36248939635 scopus 로고    scopus 로고
    • High selfing and high inbreeding depression in peripheral populations of Juncus atratus
    • Michalski S, Durka W. 2007. High selfing and high inbreeding depression in peripheral populations of Juncus atratus. Molecular Ecology 16: 4715-4727.
    • (2007) Molecular Ecology , vol.16 , pp. 4715-4727
    • Michalski, S.1    Durka, W.2
  • 33
    • 33745972942 scopus 로고    scopus 로고
    • Geographic structure of pollinator communities, reproductive assurance, and the evolution of self-pollination
    • Moeller DA. 2006. Geographic structure of pollinator communities, reproductive assurance, and the evolution of self-pollination. Ecology 87: 1510-1522.
    • (2006) Ecology , vol.87 , pp. 1510-1522
    • Moeller, D.A.1
  • 34
    • 0027332931 scopus 로고
    • Relationships between flowering phenology and life history strategies in tundra plants
    • Molau U. 1993. Relationships between flowering phenology and life history strategies in tundra plants. Arctic and Alpine Research 25: 391-402.
    • (1993) Arctic and Alpine Research , vol.25 , pp. 391-402
    • Molau, U.1
  • 35
    • 0031878438 scopus 로고    scopus 로고
    • Isolation and characterization of microsatellites of Rhododendron metternichii Sieb. et Zucc var hondoense Nakai
    • Naito K, Isagi Y, Nakagoshi N. 1998. Isolation and characterization of microsatellites of Rhododendron metternichii Sieb. et Zucc. var. hondoense Nakai. Molecular Ecology 7: 927-928.
    • (1998) Molecular Ecology , vol.7 , pp. 927-928
    • Naito, K.1    Isagi, Y.2    Nakagoshi, N.3
  • 36
    • 0036380682 scopus 로고    scopus 로고
    • Inter-parent distance affects reproductive success in two clonal shrubs, Vaccinium myrtillus and Vaccinium vitis-idaea (Ericaceae)
    • Nuortila C, Tuomi J, Laine K. 2002. Inter-parent distance affects reproductive success in two clonal shrubs, Vaccinium myrtillus and Vaccinium vitis-idaea (Ericaceae). Canadian Journal of Botany 80: 875-884.
    • (2002) Canadian Journal of Botany , vol.80 , pp. 875-884
    • Nuortila, C.1    Tuomi, J.2    Laine, K.3
  • 37
    • 33645544632 scopus 로고    scopus 로고
    • Early-acting inbreeding depression in a clonal dwarf shrub, Vaccinium myrtillus, in a northern boreal forest
    • Nuortila C, Tuomi J, Aspi J, Laine K. 2006. Early-acting inbreeding depression in a clonal dwarf shrub, Vaccinium myrtillus, in a northern boreal forest. Annales Botanici Fennici 43: 36-48.
    • (2006) Annales Botanici Fennici , vol.43 , pp. 36-48
    • Nuortila, C.1    Tuomi, J.2    Aspi, J.3    Laine, K.4
  • 38
    • 0029310503 scopus 로고
    • Microsatellite analysis of population structure in Canadian polar bears
    • Paetkau D, Calvert W, Stirling I, Strobeck C. 1995. Microsatellite analysis of population structure in Canadian polar bears. Molecular Ecology 4: 347-354.
    • (1995) Molecular Ecology , vol.4 , pp. 347-354
    • Paetkau, D.1    Calvert, W.2    Stirling, I.3    Strobeck, C.4
  • 39
    • 17644427631 scopus 로고    scopus 로고
    • The evolution of self-fertilization and inbreeding depression under pollen discounting and pollen limitation
    • Porcher E, Lande R. 2005. The evolution of self-fertilization and inbreeding depression under pollen discounting and pollen limitation. Journal of Evolutionary Biology 18: 497-508.
    • (2005) Journal of Evolutionary Biology , vol.18 , pp. 497-508
    • Porcher, E.1    Lande, R.2
  • 40
    • 10044267928 scopus 로고    scopus 로고
    • Inbreeding depression and biased paternity after mixed-pollination in Vaccinium myrtillus L. Ericaceae)
    • Raspé O, Guillaume P, Jacquemart AL. 2004. Inbreeding depression and biased paternity after mixed-pollination in Vaccinium myrtillus L. (Ericaceae). International Journal of Plant Sciences 165: 765-771.
    • (2004) International Journal of Plant Science , vol.165 , pp. 765-771
    • Raspé, O.1    Guillaume, P.2    Jacquemart, A.L.3
  • 41
    • 0002992571 scopus 로고
    • Competition and facilitation among plants for pollination
    • Real Led. Orlando, FL: Academic Press
    • Rathcke B. 1983. Competition and facilitation among plants for pollination. In: Real Led. Pollination biology. Orlando, FL: Academic Press, 305-329.
    • (1983) Pollination Biology , pp. 305-329
    • Rathcke, B.1
  • 42
    • 0027800712 scopus 로고
    • Autogamy and inbreeding depression in mountain laurel, Kalmid latifolia (Ericaceae)
    • Rathcke B, Real I. 1993. Autogamy and inbreeding depression in mountain laurel, Kalmid latifolia (Ericaceae). American Journal of Botany 80: 143-146.
    • (1993) American Journal of Botany , vol.80 , pp. 143-146
    • Rathcke, B.1    Real, I.2
  • 43
    • 0000262278 scopus 로고
    • GENEPOP (version 1.2): Population genetic software for exact tests and ecumenicism
    • Raymond M, Rousset F. 1995. GENEPOP (version 1.2): population genetic software for exact tests and ecumenicism. Journal of Heredity 86: 248-249.
    • (1995) Journal of Heredity , vol.86 , pp. 248-249
    • Raymond, M.1    Rousset, F.2
  • 44
    • 0027158760 scopus 로고
    • A rapid CTAB DNA isolation technique useful for RAPD fingerprinting and other PCR applications
    • Stewart Jr. CN, Via LE. 1993. A rapid CTAB DNA isolation technique useful for RAPD fingerprinting and other PCR applications. BioTechniques 14: 748-750.
    • (1993) BioTechniques , vol.14 , pp. 748-750
    • Stewart, C.N.1    Via, L.E.2
  • 45
    • 0002800794 scopus 로고
    • Spatial and temporal components of resource assessment by flower-feeding insects
    • Thomson JD. 1981. Spatial and temporal components of resource assessment by flower-feeding insects. Journal of Animal Ecology 50: 49-59.
    • (1981) Journal of Animal Ecology , vol.50 , pp. 49-59
    • Thomson, J.D.1
  • 46
    • 0038472556 scopus 로고    scopus 로고
    • The life history and pollination ecology of bumblebees in the alpine zone of central Japan
    • Tomono T, Sota T. 1997. The life history and pollination ecology of bumblebees in the alpine zone of central Japan. Japanese Journal of Entomology 65: 237-255.
    • (1997) Japanese Journal of Entomology , vol.65 , pp. 237-255
    • Tomono, T.1    Sota, T.2
  • 47
    • 0028180940 scopus 로고
    • Intraseasonal variation in pollination intensity and seed set in an alpine population of Ranunculus acris in southwestern Norway
    • Totland Ø. 1994. Intraseasonal variation in pollination intensity and seed set in an alpine population of Ranunculus acris in southwestern Norway. Ecography 17: 159-165.
    • (1994) Ecography , vol.17 , pp. 159-165
    • Totland Ø1
  • 48
    • 0000660734 scopus 로고
    • Interspecific pollen transfer and competition between co-occurring plant species
    • Waser NM. 1978. Interspecific pollen transfer and competition between co-occurring plant species. Oecologia 36: 223-236.
    • (1978) Oecologia , vol.36 , pp. 223-236
    • Waser, N.M.1
  • 49
    • 0002802758 scopus 로고
    • Competition for pollination and floral character differences among sympatric plant species: A review of evidence
    • Jones CE, Little RJeds. New York, NY: Scientific and Academic Editors
    • Waser NM. 1983. Competition for pollination and floral character differences among sympatric plant species: A review of evidence. In: Jones CE, Little RJeds. Experimental handbook. New York, NY: Scientific and Academic Editors, 277-238.
    • (1983) Experimental Handbook , pp. 277-238
    • Waser, N.M.1
  • 50
    • 0021566877 scopus 로고
    • Estimating F-statistics for the analysis of population structure
    • Weir BS, Cockerham CC. 1984. Estimating F-statistics for the analysis of population structure. Evolution 38: 1358-1370.
    • (1984) Evolution , vol.38 , pp. 1358-1370
    • Weir, B.S.1    Cockerham, C.C.2
  • 51
    • 0022838722 scopus 로고
    • The ecological pollination syndromes of insect-pollinated plants in an alpine meadow
    • Yumoto T. 1986. The ecological pollination syndromes of insect-pollinated plants in an alpine meadow. Ecological Research 1: 83-95.
    • (1986) Ecological Research , vol.1 , pp. 83-95
    • Yumoto, T.1
  • 52
    • 34250246091 scopus 로고
    • Optimal foraging, plant density and the marginal value theorem
    • Zimmerman M. 1981. Optimal foraging, plant density and the marginal value theorem. Oecologia 49: 148-153.
    • (1981) Oecologia , vol.49 , pp. 148-153
    • Zimmerman, M.1


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