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Female performance in Euphorbia characias: effect of flower position on seed quantity and quality

Published online by Cambridge University Press:  22 February 2007

Xavier Espadaler*
Affiliation:
CREAF, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
Crisanto Gómez
Affiliation:
Departament de Ciències Ambientals Campus de Montilivi, 17007 Girona, Spain
*
*Correspondence Fax: 34 93 5811312 Email: Xavier.Espadaler@uab.es

Abstract

Patterns of seed mass variation in the perennial spurge Euphorbia characias(L.) (Euphorbiaceae) in three populations from north-east Spain were examined. Mature inflorescences have a distinctive structure, with a distal umbrella of rays subtending dichotomously grown cyathia. Under the umbrella, cyathia are loosely arranged on rays growing from the bases of leaves. Seed characteristics were studied, especially in relation to position along the inflorescence. Maximum inflorescence height had no effect on seed set or seed mass. Seed set did not differ between populations. Flower position along the inflorescence had a marked effect on seed set and seed mass. Seed set was higher in the distal (upper) portion of the inflorescence. Seeds from the distal area had a greater mass than those from lower parts of the inflorescence. Seeds were planted in the field and observed under natural weather conditions. The bigger seeds from the higher position in the inflorescence produced seedlings with a greater percentage emergence, which, in addition, had an increased percentage establishment than seedlings originating from the smaller seeds from lower areas of the inflorescence. For the three populations considered together, seeds from the basal (lower) portion of the inflorescence were reduced in germination by 51% and establishment by 59%. No differences in seedling dry mass were observed. Seed dispersal-related structures (elaiosome and elaiosome/load ratio) did not vary in relation to position or population. Positional effects on female performance – seed quantity and quality – may be a very strong selective pressure for the peculiar flower disposition in the architecture of E. characias.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2001

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References

Aarssen, L.W. (1995) Hypotheses for the evolution of apical dominance in plants: implications for the interpretation of overcompensation. Oikos 74, 149156.CrossRefGoogle Scholar
Aker, C.L. (1982) Regulation of flower, fruit and seed production by a monocarpic perennial, Yucca whipplei. Journal of Ecology 70, 357372.CrossRefGoogle Scholar
Baskin, C.C. and Baskin, J.M. (1998) Seeds. Ecology, biogeography, and evolution of dormancy and germination. New York, Academic Press.Google Scholar
Beattie, A.J. (1985) The evolutionary ecology of ant-plant mutualisms. Cambridge, Cambridge University Press.CrossRefGoogle Scholar
Bennett, A. and Krebs, J. (1987) Seed dispersal by ants. Trends in Ecology and Evolution 2, 291292.CrossRefGoogle Scholar
Brunet, J. (1996) Male reproductive success and variation in fruit and seed set in Aquilegia caerulea (Ranunculaceae). Ecology 77, 24582471.CrossRefGoogle Scholar
Campbell, D.R. and Halama, K.J. (1993) Resource and pollen limitations to lifetime seed production in a natural plant population. Ecology 74, 10431051.CrossRefGoogle Scholar
Cavers, P.B. and Steel, M.G. (1984) Patterns of change in seed weight over time of individual plants. The American Naturalist 124, 324335.CrossRefGoogle Scholar
Cideciyan, M.A. and Malloch, A.J.C. (1982) Effects of seed size on the germination, growth and competitive ability of Rumex crispus and Rumex obtusifolius. Journal of Ecology 70, 227232.CrossRefGoogle Scholar
Cruden, R.W. (1977) Pollen-ovule ratios: a conservative indicator of breeding systems in flowering plants. Evolution 31, 3246.CrossRefGoogle ScholarPubMed
Dawkins, R. and Dawkins, M. (1973) Decisions and the uncertainty of behaviour. Behaviour 45, 83103.Google Scholar
Diggle, P.K. (1995) Architectural effects and the interpretation of patterns of fruit and seed development. Annual Review of Ecology and Systematics 26, 531552.CrossRefGoogle Scholar
Ehrenfeld, J. (1976) Reproductive biology of three species of Euphorbia subgenus Chamaesyce (Euphorbiaceae). American Journal of Botany 63, 406413.CrossRefGoogle Scholar
Espadaler, X. and Gómez, C. (1996) Seed production, predation and dispersal in the Mediterranean myrmecochore Euphorbia characias (Euphorbiaceae). Ecography 19, 715.CrossRefGoogle Scholar
Espadaler, X. and Gómez, C. (1997a) Falling of movement of seeds and the presence of an elaiosome: its effect on ant reaction (Hymenoptera: Formicidae) in a myrmecochorous species, Euphorbia characias (Euphorbiaceae). Sociobiology 30, 175183.Google Scholar
Espadaler, X. and Gómez, C. (1997b) Soil surface searching and transport of Euphorbia characias seeds by ants. Acta Oecologica 18, 3946.CrossRefGoogle Scholar
Fenner, M. (1985) Seed ecology. London, Chapman and Hall.CrossRefGoogle Scholar
Garrison, W.J., Miller, G.L. and Raspet, R. (2000) Ballistic seed projection in two herbaceous species. American Journal of Botany 80, 12571264.CrossRefGoogle Scholar
Gómez, C. and Espadaler, X. (1998a) Aphaenogaster senilis Mayr (Hymenoptera, Formicidae): a possible parasite in the myrmecochory of Euphorbia characias (Euphorbiaceae). Sociobiology 32, 441450.Google Scholar
Gómez, C. and Espadaler, X. (1998b) Manipulación por hormigas de semillas de Euphorbia characias (Euphorbiaceae) dentro del hormiguero. Scientia gerundensis 23, 5361.Google Scholar
Gorb, S.N. and Gorb, E.V. (1999) Dropping rates of elaiosome-bearing seeds during transport by ants (Formica polyctena Foerst.): Implications for distance dispersal. Acta Oecologica 20, 509518.CrossRefGoogle Scholar
Gross, K.L. (1984) Effects of seed size and growth form on seedling establishment of six monocarpic perennial plants. Journal of Ecology 72, 369387.CrossRefGoogle Scholar
Gross, R.S. and Werner, P.A. (1983) Relationships among flowering phenology, insect visitors, and seed set of individuals: experimental studies on four co-occurring species of goldenrod (Solidago: Compositae). Ecological Monographs 53, 95117.CrossRefGoogle Scholar
Gunther, R.W. and Lanza, J. (1989) Variation in attractiveness of Trillium diaspores to a seed dispersing ant. American Midland Naturalist 122, 321328.CrossRefGoogle Scholar
Guttermann, Y. (1992) Maternal effects on seeds during development. pp. 2759 in Fenner, M. (Ed.) Seeds: the ecology of regeneration in plant communities. Wallingford, CAB International.Google Scholar
Harper, J.L. (1977) Population biology of plants. New York, Academic Press.Google Scholar
Howe, H.F. (1989) Scatter- and clump-dispersal and seedling demography: hypotheses and implications. Oecologia 79, 417426.CrossRefGoogle Scholar
Hughes, L. and Westoby, M. (1992) Effect of diaspore characteristics on removal of seeds adapted for dispersal by ants. Ecology 731, 13001312.CrossRefGoogle Scholar
Kigel, J., Lior, E., Zamir, L. and Rubin, B. (1992) Biology of reproduction in the summer annual weed Euphorbia geniculata Ortega. Weed Research 32, 317328.CrossRefGoogle Scholar
Klinkhamer, P.G.L. and DeJong, T.J. (1987) Plant size and seed production in the monocarpic perennial Cynoglossum officinale L. New Phytologist 106, 773783.CrossRefGoogle ScholarPubMed
Lortie, C.J. and Aarssen, L.W. (1999) The advantage of being tall: Higher flowers receive more pollen in Verbascum thapsus L. (Scrophulariaceae). Ecoscience 6, 6871.CrossRefGoogle Scholar
Lubbers, A.E and Christensen, N.L. (1986) Intraseasonal variation in seed production among flowers and plants of Thalictrum thalictroides. American Journal of Botany 73, 190203.CrossRefGoogle Scholar
Marshall, D.L. and Folsom, M.W. (1991) Mate choice in plants: an anatomical to population perspective. Annual Review of Ecology and Systematics 22, 3763.CrossRefGoogle Scholar
Meeuse, A.D.J., Vinkenoog, S. and Vroege, P.W. (1989) Anthecology of Euphorbia – preliminary studies. Acta Botanica Neerlandica 38, 493502.CrossRefGoogle Scholar
Melzack, R.N. and Watts, D. (1982) Variations in seed weight, germination, and seedling vigour in the yew (Taxus baccata L.) in England. Journal of Biogeography 9, 5563.CrossRefGoogle Scholar
Mitchell, R.J. (1997) Effects of pollination intensity on Lesquerella fendleri seed set: variations among plants. Oecologia 109, 382388.CrossRefGoogle ScholarPubMed
Morgan, M.T. and Schoen, D.J. (1997) The role of theory in an emerging new plant reproductive biology. Trends in Ecology and Evolution 12, 231234.CrossRefGoogle Scholar
Nakamura, R.R. (1988) Seed abortion and seed size variation within fruits of Phaseolus vulgaris: pollen donor and resource limitation effects. American Journal of Botany 75, 10031010.CrossRefGoogle Scholar
Obeso, J.R. (1993a) Selective fruit and seed maturation in Asphodelus albus Miller (Liliaceae). Oecologia 93, 564570.CrossRefGoogle ScholarPubMed
Obeso, J.R. (1993b) Seed mass variation in the perennial herb Asphodelus albus: sources of variation and position effect. Oecologia 93, 571575.CrossRefGoogle ScholarPubMed
Oostermeijer, J.G.B. (1989) Myrmecochory in Polygala vulgaris L., Luzula campestris (L.) DC, and Viola curtisii Forster in a Dutch dune area. Oecologia 78, 302311.CrossRefGoogle Scholar
Peakall, R. and Handel, S.N. (1993) Pollinators discriminate among floral heights of a sexually deceptive orchid: implications for selection. Evolution 47, 16811687.CrossRefGoogle ScholarPubMed
Primack, R.B. (1987) Relationships among flowers, fruits, and seeds. Annual Review of Ecology and Systematics 18, 409430.CrossRefGoogle Scholar
Pyke, G.H. (1981) Effects of inflorescence height and number of flowers per inflorescence on fruit set in waratahs (Telopea speciossisima). Australian Journal of Botany 29, 419424.CrossRefGoogle Scholar
Scharpf, R.F. (1970) Seed viability, germination and radicle growth of dwarf mistletoe in California. USDA Forest Service Research, Paper PSW-59. Berkeley, CA, USDA.Google Scholar
Schimpf, D.J. (1977) Seed weight of Amaranthus retroflexus in relation to moisture and length of growing season. Ecology 58, 450453.CrossRefGoogle Scholar
Simons, A.M. and Johnston, M.O. (2000) Variation in seed traits of Lobelia inflata (Campanulaceae): sources and fitness consequences. American Journal of Botany 87, 124132.CrossRefGoogle ScholarPubMed
Sokal, R.R. and Rohlf, F.J. (1995) Biometry. New York, Freeman.Google Scholar
Stanton, M.L. (1984) Seed variation in wild radish: effect of seed size on components of seedling and adult fitness. Ecology 65, 11051112.CrossRefGoogle Scholar
Strasburger, E. (1970) Tratado de botánica. Barcelona, Marín.Google Scholar
Susko, D.J. and Lovett-Doust, L. (2000) Patterns of seed mass variation and their effects on seedling traits in Alliaria petiolata (Brassicaceae). American Journal of Botany 87, 5666.CrossRefGoogle ScholarPubMed
Sutherland, S. (1987) Why hermaphroditic plants produce many more flowers than fruits: experimental tests with Agave mckelveyana. Evolution 41, 750759.CrossRefGoogle ScholarPubMed
van Rooden, J., Akkermans, L.M.A. and van der Veen, R. (1970) A study of photoblastism in seeds of some tropical weeds. Acta Botanica Neerlandica 19, 257264.CrossRefGoogle Scholar
Verbeek, N.A.M. and Boasson, R. (1995) Flowering height and postfloral elongation of flower stalks in 13 species of angiosperms. Canadian Journal of Botany 73, 723727.CrossRefGoogle Scholar
Weis, I.M. (1982) The effects of propagule size on germination and seedling growth in Mirabilis hirsuta. Canadian Journal of Botany 60, 18681874.CrossRefGoogle Scholar
Westoby, M., Jurado, E. and Leishman, M. (1992) Comparative evolutionary ecology of seed size. Trends in Ecology and Evolution 7, 368372.CrossRefGoogle ScholarPubMed
Wolfe, L.M. (1992) Why does the size of reproductive structures decline through time in Hydrophyllum appendiculatum (Hydrophyllaceae): developmental constraints vs. resource limitation. American Journal of Botany 79, 12861290.CrossRefGoogle Scholar
Wyatt, R. (1982) Inflorescence architecture: how flower number, arrangement, and phenology affect pollination and fruit-set. American Journal of Botany 69, 585594.CrossRefGoogle Scholar
Yanful, M. and Maun, M.A. (1996) Effects of burial of seeds and seedlings from different seed sizes on the emergence and growth of Strophostyles helvola. Canadian Journal of Botany 74, 13221330.CrossRefGoogle Scholar