Abstract
The goal of this study was to elucidate the sources of seed size variation in Hydrophyllum appendiculatum, an outcrossing, biennial plant. The genetic basis of seed size variation was examined with a diallel breeding design. The analysis did not reveal any evidence for additive genetic variance, suggesting that seed size could not evolve in response to natural selection. A series of greenhouse experiments was conducted to determine the sensitivity of seed weight to a number of ecological variables. Seed weight was affected by inbreeding depression: seeds produced by self-pollinations were significantly lighter that outcrossed seeds. Maternal plants did not differentially provision seeds that were the result of crosses between subpopulations (separated by 300 m) or between populations (separated by 1.7 km). Mean seed size was independent of the number of outcrossed pollen donors (one vs. many) that sired seeds on an inflorescence; however, the variance was greater on inflorescences pollinated by multiple donors. Direct manipulations of the abiotic environment showed that seed size was greater on plants growing under full sunlight compared to shaded plants. Seed size was unaffected by soil type, fertilizer addition, or defoliation. Finally, I determined the effect of varying pollination intensity at the level of a single inflorescence, and at the whole plant level. Seed weight was greatest on plants that had only 1 and 5 inflorescences pollinated, and least on those that had 10 and 20 pollinated. At the inflorescence level, seed weights were greatest on those where all flowers were pollinated, compared to inflorescences where only half of the flowers were pollinated. Perhaps the greatest contributor to variance in seed size in this species was the temporal decline within plants through the flowering season. These results indicate that maternal plants are not capable of producing uniform seed crops. Rather, the final distribution of seed size produced by plants within a population will necessarily vary and be the result of pollination effects, heterogeneity in the abiotic environment, and developmental constraints.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Alexander HM, Wulff RD (1985) Experimental ecological genetics in Plantago. X. The effects of maternal temperature on seed and seedling characters in P. lanceolata. J Ecol 73: 271–282
Antonovics J (1971) The effects of a heterogeneous environment on the genetics of natural populations. Am Sci 5: 593–599
Antonovics J, Schmitt J (1986) Paternal and maternal effects on propagule size in Anthoxanthum odoratum. Oecologia 69: 277–282
Bentley S, Whittaker JB, Mallock AJC (1980) Field experiments on the effects of grazing by a chrysomelid beetle (Gastrophysa viridula) on seed production and quality in Rumex obtusifolius and Rumex crispus. J Ecol 68: 671–674
Bertin R (1986) Consequences of mixed pollinations in Campsis radicans. Oecologia 70: 1–5
Brink RA, Cooper DC (1940) Double fertilization and development of the seed in angiosperms. Bot Gaz 102: 1–25
Carlquist S (1969) Toward acceptable evolutionary interpretations of floral anatomy. Phytomorphology 19: 332–362
Cavers PB, Steel MG (1984) Patterns of change in seed weights over time on individual plants. Am Nat 124: 324–335
Cook RE (1975) The photoinductive control of seed weight in Chenopodium rubrum L. Am J Bot 62: 427–431
Dawson TE, Ehleringer JR (1991) Ecological correlates of seed mass variation in Phoradendron juniperinum, a xylem-tapping mistletoe. Oecologia 85: 332–342
Devlin B (1988) The effects of stress on reproductive characters of Lobelia cardinalis. Ecology 69: 1716–1720
Dickerson GE (1969) Techniques for research in quantitative animal genetics. In: Techniques and procedures in animal science. American Society of Animal Scientists. Albany, pp 36–79
Dolan RW (1984) The effect of seed size and maternal source on individual size in a population of Ludwigia leptocarpa (Onagraceae). Am J Bot 71: 1302–1307
Falconer DS (1981) Introduction to quantitative genetics. Longman, London
Galen C (1989) Measuring the pollinator-mediated selection in morphometric floral traits: bumblebees and the alpine sky pilot, Polemonium viscosum. Evolution 43: 882–890
Galen C, Plowright RC, Thomson JD (1985) Floral biology and regulation of seed set and seed size in the lily, Clintonia borealis. Am J Bot 72: 1544–1552
Glewen KL, Vogel KP (1984) Partitioning the genetic variability for seedling growth in sand bluestem into seed size and seedling vigor components. Crop Sci 24: 137–141
Gross KL (1984) Effects of seed size and growth form on seedling establishment of six monocarpic perennial plants. J Ecol 72: 369–387
Gross KL, Kromer ML (1986) Seed weight effects on growth and reproduction in Oenothera biennis L. Bull Torr Bot Club 113: 252–258
Gutterman Y (1980/1981) Influences on seed germinability: phenotypic maternal effects during seed germination. Isr J Bot 29: 105–11
Harper JL, Obeid M (1967) Influence of seed size and depth of sowing on the establishment and growth of varieties of fiber and oil seed flax. Crop Sci 7: 527–532
Howe HF, Richter WM (1982) Effect of seed size on seedling size in Virola surinamensis: a within and between tree analysis. Oecologia 53: 347–351
Janzen DH, DeVries P, Gladstone DE, Higgins ML, Lewinsohn TM (1980) Self-and cross-pollination of Encyclia cordigera (Orchidaceae) in Santa Rosa National Park, Costa Rica. Biotropica 12: 72–74
Kalisz S (1989) Fitness consequences of mating system, seed weight, and emergence date in a winter annual, Collinsia verna. Evolution 43: 1263–1272
Kress WJ (1981) Sibling competition and evolution of pollen unit, ovule number, and pollen vector in angiosperms. Syst Bot 6: 101–112
Lalonde RG, Roitberg BD (1989) Resource limitation and offspring size and number trade-offs in Cirsium arvense (Asteraceae). Am J Bot 76: 1107–1113
Lee TD, Bazzaz FA (1982) Regulation of fruit and seed production in an annual legume, Cassia fasciculata. Ecology 63: 1363–1373
Levin DA (1984) Inbreeding depression and proximity dependent crossing success in Phlox drummondil. Evolution 38: 116–127
Levin DA, Kerster HW (1974) Gene flow in seed plants. Evol Biol 7: 139–220
Marshall DL, Ellstrand NC (1986) Sexual selection in Raphanus sativus: experimental data on non-random fertilization, maternal choice, and consequences of multiple paternity. Am Nat 127: 446–461
Maun MA, Cavers PB (1971) Seed production and dormancy in Rumex crispus. II. The effects of removal of various proportions of flowers at anthesis. Can J Bot 49: 1841–1848
Mazer SJ (1987) Parental effects on seed development and seed yield in Raphanus raphanistrum: implications for natural and sexual selection. Evolution 41: 355–371
Mazer SJ, Wolfe LM (1992) Planting density influences the expression of genetic variation in seed mass in wild radish (Raphanus sativus L.: Brassicaceae). Am J Bot 79: 1185–1193
Mazer SJ, Snow AA, Stanton ML (1986) Fertilization dynamics and parental effects upon fruit development in Raphanus raphanistrum: consequences for seed size variation. Am J Bot 73: 500–511
McGinley MA, Temme DH, Geber MA (1987) Patental investment in offspring in variable environments: theoretical and empirical considerations. Am Nat 130: 370–398
Nakamura RR, Stanton ML (1989) Embryo growth and seed size in Raphanus sativus: maternal and paternal effects in vivo and in vitro. Evolution 43: 1435–1443
Newport MEA (1989) A test for proximity-dependent outcrossing in the Alpine Skypilot, Polemonium viscosum. Evolution 43: 1110–1113
Nieuwhof M, Garretsen F, van Oeveren JC (1989) Maternal and genetic effects on seed weight of tomato and effects of seed weight on growth of genotypes of tomato (Lycopersicon esculentum Mill.). Plant Breeding 102: 248–254
Parrish JAD, Bazzaz FA (1985) Nutrient content of Abutilon theophrastii seeds and the competitive ability of the resulting plants. Oecologia 65: 247–251
Pate JS, Farrington P (1981) Fruit set in Lupinus angustifolius cv. Unicrop. II. Assimilate flow during flowering and early fruiting. Aust J Plant Physiol 8: 307–318
Pederson MW, Peterson HL, Bohart GE, Levin MD (1956) A comparison of the effects of complete and partial cross-pollination of alfalfa on pod sets, seeds per pod, and pod and seed weight. Agro J 48: 177–180
Pitelka LF, Stanton DS, Peckenham MO (1980) Effects of light and density on resource allocation in a forest herb, Aster acuminatus (Compositae). Am J Bot 67: 942–948
Pitelka LF, Thayer ME, Hansen SB (1983) Variation in achene weight in Aster acuminatus. Can J Bot 61: 1415–1420
Pittman KE, Levin DA (1989) Effects of parental identities and environment on components of crossing success in Phlox drummondii. Am J Bot 76: 409–418
Price MV, Waser NM (1979) Pollen dispersal and optimal outcrossing in Delphinium nelsonii. Nature 277: 294–296
Primack R (1987) Relationships among flowers, fruits, and seeds. Annu Rev Ecol Syst 18: 409–430
Roach DA (1986) Variation in seed and seedling size in Anthoxanthum odoratum. Am Midl Nat 117: 258–264
Roach DA, Wulff RD (1987) Maternal effects in plants. Annu Rev Ecol Syst 18: 209–235
Salisbury EJ (1942) The reproductive capacity of plants. Bell, London
Salisbury EJ (1958) Spergularia salina and S. marginata and their heteromorphic seeds. Kew Bull 1: 41–51
SAS Institute (1985) SAS User's Guide, Version 5. SAS Institute, Cary
Schaal BA (1978) Measurement of gene flow in Lupinus texensis. Nature 284: 450–451
Schaal BA (1980) Reproductive capacity and seed size in Lupinus texensis. Am J Bot 67: 703–709
Schemske DW (1984) Population structure and local selection in Impatiens pallida (Balsaminaceae), a selfing annual. Evolution 38: 817–832
Schemske DW, Horvitz CC (1989) Temporal variation in selection on a floral character. Evolution 43: 461–465
Schemske DW, Pautler LP (1984) The effects of pollen composition on fitness components in a neotropical herb. Oecologia 62: 31–36
Schwaegerle KE, Levin DA (1990) Quantitative genetics of seed size variation in Phlox. Evol Ecol 4: 143–148
Shore JS (1993) Pollination genetics of the common milkweed, Asclepias syriaca L. Heredity 70: 101–108
Sinnott EW (1921) The relationship between body size and organ size in plants. Am Nat 55: 385–403
Smith CC, Fretwell SD (1974) The optimal balance between size and number of offspring. Am Nat 108: 499–506
Sobrevila C (1988) Effects of distance between pollen donor and pollen recipient on fitness components in Espeletia schultzii. Am J Bot 75: 701–724
Sokal RR, Rohlf FJ (1981) Biometry. Freeman, New York
Sorenson FC, Miles RS (1974) Self pollination effects on douglas fir and ponderosa pine: seeds and seedlings. Silvae Genet 23: 135–138
Stanton ML (1984) Seed variation in wild radish: effect of seed size on components of seedling and adult fitness. Ecology 65: 1105–1112
Stanton ML (1985) Seed size and emergence time within a stand of wild radish (Raphanus raphanistrum L.): the establishment of a fitness hierarchy. Oecologia 67: 524–531
Stanton ML, Bereczky JK, Hasbrouck HD (1987) Pollination thoroughness and maternal yield regulation in wild radish, Raphanus raphanistrum (Brassicaceae). Oecologia 74: 68–76
Stratton DA (1989) Competition prolongs expression of maternal effects in seedlings of Erigeron annuus (Asteraceae). Am J Bot 76: 1646–1653
Temme DH (1986) Seed size variability: a consequence of variable genetic quality among offspring? Evolution 40: 414–417
Thompson JN, Pellmyr O (1989) Orlgins of variance in seed number and seed mass: interaction of sex expression and herbivory in Lomatium salmoniflorum. Oecologia 79: 395–402
Turner ME, Stephens JC, Anderson WW (1982) Homozygosity and patch structure in plant populations as a result of nearest-neighbor pollination. Proc Natl Acad Sci USA 79: 203–207
Waller DM (1985) The genesis of size hierarchies in seedling populations of Impatiens capensis Meerb. New Phytol 100: 243–260
Wareing PF, Khalifa M, Treharne RJ (1968) Rate limiting processes in photosynthesis at saturating light intensities. Nature 220: 453–457
Weis IM (1982) The effects of propagule size on germination and seedling growth in Mirabilis hirsuta. Can J Bot 60: 1868–1874
Weis AE, Hollenbach HG, Abrahamson WG (1987) Genetic and maternal effects on seedling characters of Solidago altissima (Compositae). Am J Bot 74: 1476–1486
Westoby M, Rice B (1982) Evolution of seed plants and inclusive fitness of plant tissues. Evolution 36: 713–724
Winn AA (1991) Proximate and ultimate sources of within-individual variation in seed mass in Prunella vulgaris (Lamiaceae). Am J Bot 78: 838–844
Wolfe LM (1990) Regulation of reproductive success in Hydrophyllum appendiculatum, a biennial plant. PhD Thesis, University of Illinois
Wolfe LM (1992) Why does the size of reproductive structures decline through time in Hydrophyllum appendiculatum (Hydrophyllaceae)? developmental constraints vs. resource limitation. Am J Bot 79: 1286–1290
Wolfe LM (1993a) Inbreeding depression in Hydrophyllum appendiculatum: the influence of maternal effects, crowding, and parental mating history. Evolution 47: 374–386
Wolfe LM (1993b) Fitness consequences of a flower color polymorphism in an outcrossing, biennial plant, Hydrophyllum appendiculatum. Am Midl Nat 129: 405–408
Wolfe LM, Barrett SCH (1989) Patterns of pollen removal and deposition in tristylous Pontederia cordata L. (Pontedericeae). Biol J Linn Soc 36: 317–329
Wolfe LM, Shore JS (1992) The mating system of Hydrophyllum appendiculatum, a protandrous species. Sex Plant Reprod 5: 239–245
Wulff RD (1986) Seed size variation in Desmodium paniculatum. III. Effects on reproductive yield and competitive ability. J Ecol 74: 115–121
Young HJ, Stanton ML (1990) Influences of floral variation on pollen removal and seed production in wild radish. Ecology 71: 536–547
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wolfe, L.M. The genetics and ecology of seed size variation in a biennial plant, Hydrophyllum appendiculatum (Hydrophyllaceae). Oecologia 101, 343–352 (1995). https://doi.org/10.1007/BF00328821
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00328821