title: The presence of a below-ground neighbour alters within-plant seed size distribution in Phaseolus vulgaris.
abstract: OBJECTIVE
  Considerable variation in seed size commonly exists within plants, and is believed to be favoured under natural selection. This study aims to examine the extent to which seed size distribution depends on the presence of competing neighbour plants.
  
  
  METHODS
  Phaseolus vulgaris plants rooting with or without a conspecific neighbour were grown in soil with high or low nutrient availability. Seeds were harvested at the end of the growth cycle, the total nitrogen and phosphorus invested in seed production were measured and within-plant seed size distribution was quantified using a set of statistical descriptors.
  
  
  RESULTS
  Exposure to neighbours' roots induced significant changes in seed size distribution. Plants produced proportionally more large seeds and fewer small ones, as reflected by significant increases in minimal seed size, mean seed size, skewness and Lorenz asymmetry coefficient. These effects were different from, and in several cases opposite to, the responses when the soil nutrient level was reduced, and were significant after correction for the amount of resources invested in seed production.
  
  
  CONCLUSIONS
  Below-ground neighbour presence affects within-plant seed size distribution in P. vulgaris. This effect appears to be non-resource-mediated, i.e. to be independent of neighbour-induced effects on resource availability. It implies that, based on current environmental cues, plants can make an anticipatory adjustment of their investment strategy in offspring as an adaptation to the local environment in the future.
authors.affiliation: Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands B.Chen@uu.nl.
authors.forename: Bin J W
authors.initials: BJ
authors.lastname: Chen
authors.affiliation: Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands.
authors.forename: Heinjo J
authors.initials: HJ
authors.lastname: During
authors.affiliation: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Vermeulen
authors.affiliation: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands.
authors.forename: Niels P R
authors.initials: NP
authors.lastname: Anten
mesh_terms: D018533:Biomass; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism*; D027805:Phaseolus / Q000254:growth & development / Q000502:physiology*; D010758:Phosphorus / Q000378:metabolism*; D063148:Plant Dispersal; D018517:Plant Roots / Q000254:growth & development / Q000502:physiology*; D012639:Seeds / Q000254:growth & development / Q000502:physiology*; D012987:Soil
chemical_list: D012987:Soil; D010758:Phosphorus; D009584:Nitrogen
keywords: Anticipatory maternal effect; Phaseolus vulgaris; bet-hedging; game theory; kidney bean; neighbour detection; root competition; seed size variation; seed-setting; size inequality; skewness
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