Register      Login
Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE

Influence of seed dimorphism and provenance on seed morphology, dispersal, germination and seedling growth of Brachyscome ciliaris (Asteraceae)

Rina Aleman A F , Manfred Jusaitis B C , Joan Gibbs A , Phillip Ainsley B D , Fleur Tiver E and Sophie Petit A
+ Author Affiliations
- Author Affiliations

A Sustainable Environments Research Group, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia.

B South Australian Seed Conservation Centre, Botanic Gardens of Adelaide, North Terrace, Adelaide, SA 5000, Australia.

C Department of Ecology & Environmental Science, School of Biological Sciences, University of Adelaide, SA 5005, Australia.

D Zoos SA, Frome Road, Adelaide, SA 5000, Australia.

E PO Box 158, Norton Summit, SA 5136, Australia.

F Corresponding author. Email: rina.aleman@yahoo.com

Australian Journal of Botany 63(8) 705-713 https://doi.org/10.1071/BT15142
Submitted: 18 June 2015  Accepted: 20 October 2015   Published: 9 December 2015

Abstract

Brachyscome ciliaris is a floriferous Australian native daisy, with potential for use as a horticultural species. The species is hardy and seeds are relatively easy to germinate, but it is unique within the Brachyscome genus in that seeds are distinctly dimorphic. Within a fruiting capitulum, ray seeds are smooth and narrow with a minute pappus, whereas disc seeds have broad flat wings with curled hairs and a longer pappus than that of ray seeds. Both seed morphs, collected from five populations of the species, were tested to determine differences in their morphology, germination speed and percentage, seedling growth and wind-dispersal characteristics. Ray seeds were generally lighter and smaller than disc seeds and their length varied significantly with provenance. Dormancy levels of the two seed morphs and growth of ray- and disc-derived seedlings did not differ significantly, but differences were significant among the five populations tested. Seeds germinated readily, and germination was optimal under winter or summer conditions and lower in spring or autumn. Seed production by plants raised from ray or disc seeds was identical, but Noora-sourced plants yielded more seed than did plants sourced from the other provenances tested. Seed size, germination and plant growth of B. ciliaris varied significantly among populations. Winged disc seeds were dispersed slightly further by wind than were wingless ray seeds. We concluded that dormancy, germination and seed-yield characteristics of B. ciliaris were all influenced more by seed provenance than by seed morph (ray or disc).

Additional keywords: Brachycome, dimorphic, disc seed, disk seed, dormancy, ray seed, wind dispersal.


References

Aguado M, Martínez-Sánchez JJ, Reig-Armiñana J, García-Breijo FJ, Franco JA, Vicente MJ (2011) Morphology, anatomy and germination response of heteromorphic achenes of Anthemis chrysantha J.Gay (Asteraceae), a critically endangered species. Seed Science Research 21, 283–294.
Morphology, anatomy and germination response of heteromorphic achenes of Anthemis chrysantha J.Gay (Asteraceae), a critically endangered species.Crossref | GoogleScholarGoogle Scholar |

Aguado M, Vicente MJ, Miralles J, Franco JA, Martínez-Sánchez JJ (2012) Aerial seed bank and dispersal traits in Anthemis chrysantha (Asteraceae), a critically endangered species. Flora 207, 275–282.
Aerial seed bank and dispersal traits in Anthemis chrysantha (Asteraceae), a critically endangered species.Crossref | GoogleScholarGoogle Scholar |

Andersson L, Milberg P (1998) Variation in seed dormancy among mother plants, populations and years of seed collection. Seed Science Research 8, 29–38.
Variation in seed dormancy among mother plants, populations and years of seed collection.Crossref | GoogleScholarGoogle Scholar |

Brãndel M (2004) Dormancy and germination of the heteromorphic achenes of Bidens frondosa. Flora 199, 228–233.
Dormancy and germination of the heteromorphic achenes of Bidens frondosa.Crossref | GoogleScholarGoogle Scholar |

Buoro M, Carlson SM (2014) Life-history syndromes: integrating dispersal through space and time. Ecology Letters 17, 756–767.
Life-history syndromes: integrating dispersal through space and time.Crossref | GoogleScholarGoogle Scholar | 24690406PubMed |

Bureau of Meteorology (2015) ‘Australian Bureau of Meteorology climate data online.’ Available at http://www.bom.gov.au/climate/data/ [accessed 7 October 2015].

El-Keblawy A (2003) Effects of achene dimorphism on dormancy and progeny traits in the two ephemerals Hedypnois cretica and Crepis aspera (Asteraceae). Canadian Journal of Botany 81, 550–559.
Effects of achene dimorphism on dormancy and progeny traits in the two ephemerals Hedypnois cretica and Crepis aspera (Asteraceae).Crossref | GoogleScholarGoogle Scholar |

Evans MEK, Dennehy JJ (2005) Germ banking: bet-hedging and variable release from egg and seed dormancy. The Quarterly Review of Biology 80, 431–451.
Germ banking: bet-hedging and variable release from egg and seed dormancy.Crossref | GoogleScholarGoogle Scholar |

Fenner M (1991) The effects of the parent environment on seed germinability. Seed Science Research 1, 75–84.
The effects of the parent environment on seed germinability.Crossref | GoogleScholarGoogle Scholar |

Fenner M, Thompson K (2004) ‘The ecology of seeds.’ (Cambridge University Press: Cambridge, UK)

Gibson JP (2001) Ecological and genetic comparison between ray and disc achene pools of the heteromorphic species Prionopsis ciliata (Asteraceae). International Journal of Plant Sciences 162, 137–145.
Ecological and genetic comparison between ray and disc achene pools of the heteromorphic species Prionopsis ciliata (Asteraceae).Crossref | GoogleScholarGoogle Scholar |

Harper JL, Lovell PH, Moore KG (1970) The shapes and sizes of seeds. Annual Review of Ecology and Systematics 1, 327–356.
The shapes and sizes of seeds.Crossref | GoogleScholarGoogle Scholar |

Imbert E, Escarre J, Lepart J (1996) Achene dimorphism and among-population variation in Crepis sancta (Asteraceae). International Journal of Plant Sciences 157, 309–315.
Achene dimorphism and among-population variation in Crepis sancta (Asteraceae).Crossref | GoogleScholarGoogle Scholar |

Leverett LD, Jolls CL (2014) Cryptic seed heteromorphism in Packera tomentosa (Asteraceae): differences in mass and germination. Plant Species Biology 29, 169–180.
Cryptic seed heteromorphism in Packera tomentosa (Asteraceae): differences in mass and germination.Crossref | GoogleScholarGoogle Scholar |

McEvoy PB (1984) Dormancy and dispersal in dimorphic achenes of tansy ragwort, Senecio jacobaea L. (Compositae). Oecologia 61, 160–168.
Dormancy and dispersal in dimorphic achenes of tansy ragwort, Senecio jacobaea L. (Compositae).Crossref | GoogleScholarGoogle Scholar |

Menges ES (1991) Seed germination percentage increases with population size in a fragmented prairie species. Conservation Biology 5, 158–164.
Seed germination percentage increases with population size in a fragmented prairie species.Crossref | GoogleScholarGoogle Scholar |

Ouborg NJ, Van Treuren R (1995) Variation in fitness-related characters among small and large populations of Salvia pratensis. Journal of Ecology 83, 369–380.
Variation in fitness-related characters among small and large populations of Salvia pratensis.Crossref | GoogleScholarGoogle Scholar |

Ruiz de Clavijo E, Jiménez MJ (1998) The influence of achene type and plant density on growth and biomass allocation in the heterocarpic annual Catananche lutea (Asteraceae). International Journal of Plant Sciences 159, 637–647.
The influence of achene type and plant density on growth and biomass allocation in the heterocarpic annual Catananche lutea (Asteraceae).Crossref | GoogleScholarGoogle Scholar |

Salkin E, Thomlinson G, Armstrong B, Courtney B, Schaumann M (1995) ‘Australian Brachyscomes.’ (The Australian Daisy Study Group: Melbourne)

Schütz W, Rave G (1999) The effect of cold stratification and light on the seed germination of temperate sedges (Carex) from various habitats and implications for regenerative strategies. Plant Ecology 144, 215–230.
The effect of cold stratification and light on the seed germination of temperate sedges (Carex) from various habitats and implications for regenerative strategies.Crossref | GoogleScholarGoogle Scholar |

Short PS (2014) A taxonomic review of Brachyscome Cass. s.lat. (Asteraceae: Astereae), including descriptions of a new genus, Roebuckia, new species and new infraspecific taxa. Journal of the Adelaide Botanic Gardens 28, 1–219.

Silvertown JW (1984) Phenotypic variety in seed germination behavior: the ontogeny and evolution of somatic polymorphism in seeds. American Naturalist 124, 1–16.
Phenotypic variety in seed germination behavior: the ontogeny and evolution of somatic polymorphism in seeds.Crossref | GoogleScholarGoogle Scholar |

Susko DJ, Lovett-Doust L (2000) Patterns of seed mass variation and their effects on seedling traits in Alliaria petiolata. American Journal of Botany 87, 56–66.
Patterns of seed mass variation and their effects on seedling traits in Alliaria petiolata.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3Mngs1GqsQ%3D%3D&md5=e8ba638661f157cd92ab00f502562693CAS | 10636830PubMed |

State Herbarium of South Australia (2015) ‘Census of South Australian plants, algae and fungi.’ (Department of Environment, Water and Natural Resources: Adelaide). Available at http://www.flora.sa.gov.au/census.shtml [Verified 10 November 2015]

Tanowitz BD, Salopek PF, Mahall BE (1987) Differential germination of ray and disc achenes in Hemizonia increscens (Asteraceae). American Journal of Botany 74, 303–312.
Differential germination of ray and disc achenes in Hemizonia increscens (Asteraceae).Crossref | GoogleScholarGoogle Scholar |

Thomson FJ, Moles AT, Auld TD, Kingsford RT (2011) Seed dispersal distance is more strongly correlated with plant height than with seed mass. Journal of Ecology 99, 1299–1307.
Seed dispersal distance is more strongly correlated with plant height than with seed mass.Crossref | GoogleScholarGoogle Scholar |

Turner SR, Merritt DJ, Renton MS, Dixon KW (2009) Seed moisture content affects afterripening and smoke responsiveness in three sympatric Australian native species from fire-prone environments. Austral Ecology 34, 866–877.
Seed moisture content affects afterripening and smoke responsiveness in three sympatric Australian native species from fire-prone environments.Crossref | GoogleScholarGoogle Scholar |

van Mölken T, Jorritsma-Wienk LD, van Hoek PHW, de Kroon H (2005) Only seed size matters for germination in different populations of the dimorphic Tragopogon pratensis subsp. pratensis (Asteraceae). American Journal of Botany 92, 432–437.
Only seed size matters for germination in different populations of the dimorphic Tragopogon pratensis subsp. pratensis (Asteraceae).Crossref | GoogleScholarGoogle Scholar | 21652419PubMed |

Venable DL (1985) The evolutionary ecology of seed heteromorphism. The American Naturalist 126, 577–595.
The evolutionary ecology of seed heteromorphism.Crossref | GoogleScholarGoogle Scholar |

Venable DL, Levin DA (1985) Ecology of achene dimorphism in Heterotheca latifolia. Journal of Ecology 73, 743–755.
Ecology of achene dimorphism in Heterotheca latifolia.Crossref | GoogleScholarGoogle Scholar |

Wagmann K, Hautekèete N, Piquot Y, Meunier C, Schmitt SE, Van Dijk H (2012) Seed dormancy distribution: explanatory ecological factors. Annals of Botany 110, 1205–1219.
Seed dormancy distribution: explanatory ecological factors.Crossref | GoogleScholarGoogle Scholar | 22952378PubMed |

Wang BC, Smith TB (2002) Closing the seed dispersal loop. Trends in Ecology & Evolution 17, 379–385.
Closing the seed dispersal loop.Crossref | GoogleScholarGoogle Scholar |

Weiher E, van der Werf A, Thompson K, Roderick M, Gardiner E, Eriksson O (1999) Challenging Theophrastus: a common core list of plant traits for functional ecology. Journal of Vegetation Science 10, 609–620.
Challenging Theophrastus: a common core list of plant traits for functional ecology.Crossref | GoogleScholarGoogle Scholar |

Yang F, Baskin JM, Baskin CC, Yang X, Cao D, Huang Z (2015) Effects of germination time on seed morph ratio in a seed-dimorphic species and possible ecological significance. Annals of Botany 115, 137–145.
Effects of germination time on seed morph ratio in a seed-dimorphic species and possible ecological significance.Crossref | GoogleScholarGoogle Scholar | 25395107PubMed |

Zhang J (1993) Seed dimorphism in relation to germination and growth of Cakile edentula. Canadian Journal of Botany 71, 1231–1235.
Seed dimorphism in relation to germination and growth of Cakile edentula.Crossref | GoogleScholarGoogle Scholar |