日時 9月12日(水) 16:30

場所 北大地球環境A棟 804号室

Effects of size-dependent competition and morphological plasticity on plant biomass-density relationships

Peter Stoll
(低温研 学振外国人特別研究員)

Abstract: Quantitative relationships between plant biomass, density and mortality have been described, but mechanistic explanations for the form of biomass-density relationships and for differences among plant species are still lacking. An individual-based, spatially-explicit model of plant growth and competition predicts effects of size-dependent competition on biomass-density relationships. Because of higher mortality rates under asymmetric (large plants suppress small plants) compared to symmetric (large and small plants get equal shares) competition, the amount of biomass at a given density is lower under asymmetric than symmetric competition. We experimentally tested this prediction using genetically modified Arabidopsis plants that are "far-red blind". Such plants show reduced morphological plasticity, thus increasing the asymmetry of competition. As predicted, blinded plants showed increased mortality and lower biomass in relation to density compared to wild type populations undergoing more symmetric competition. Our results highlight the importance of size-dependent competition and morphological plasticity for biomass-density relationships, and may explain some of the observed differences among plant species.


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