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Abstract Detail

Developmental and Structural Section

Randle , April Michelle [1], Diggle, Pamela [1].

The role of flower position and sex in explaining intra-plant variation in flower size.

Indentifying the factors that contribute to intra-plant variation in floral size is critical for addressing several key questions in plant evolutionary and developmental biology. In plant species with unisexual flowers, differences in floral size are often attributed to adaptive differences in allocation to male or female function. However, the sexual identity of a flower is often confounded with location within an inflorescence. In some species,flower position alone can explain the differences between sexes in floral size. Most studies of positional effects on flower size have been conducted in simple, raceme-like inflorescences. Here, we examine flower size variation within compound umbels of eight species of Apiaceae that vary in their sexual expression (hermaphrodite, weakly-andromonoecious,strongly-andromonoecious). We find that in andromonoecious species of Apiaceae, both sex and flower position influence the size of secondary sexual characters. Hermaphroditic species also show flower size differences related to position. The differences in size that are related to flower position within an inflorescence do not appear to be due to gradients of resource availability, but rather appear to be due the inherent variation found in repetitive units within a plant (e.g.,plant architecture).

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1 - University of Colorado , Ecology and Evolutionary Biology, Ramaley N122 , Boulder , CO, 80309-0334, USA

floral size variation
plant architecture
sexual dimporphism

Presentation Type: Oral Paper:Papers for Sections
Session: 16
Location: Lindell A/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 2:15 PM
Number: 16004
Abstract ID:344

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