AN ANALYSIS OF VARIABILITY IN SEED SETTLING VELOCITIES OF SEVERAL WIND-DISPERSED ASTERACEAE
1Department of Ecology and Evolutionary Biology, University of California, Irvine, California, 92717.
American Journal of Botany
|August 25, 2018
Summary
Seed settling velocity is a key indicator of plant dispersal ability. Introduced Asteraceae species and annuals exhibit lower settling velocities, suggesting varied dispersal strategies.
Area of Science:
- Ecology
- Plant Biology
- Evolutionary Biology
Background:
- Dispersal is a critical life history trait for plants.
- Seed settling velocity can serve as a proxy for dispersal ability, especially in wind-dispersed species with plumose structures.
Purpose of the Study:
- To measure and compare seed settling velocities across eight Asteraceae species.
- To investigate variation in settling velocities at different hierarchical levels (species, plant, inflorescence, seed).
- To determine if introduced species or annual life histories correlate with different dispersal strategies.
Main Methods:
- Settling velocities were measured for seeds of eight Asteraceae species.
- Analysis of variance was used to partition variation in settling velocities.
- Mean settling velocities were compared between native and introduced species, and between annuals and perennials.
Main Results:
- Significant variation in seed settling velocity was observed among species, plants within species, and inflorescences/seeds within plants.
- Introduced Asteraceae species demonstrated significantly lower settling velocities compared to native species.
- Annual species exhibited lower settling velocities than biennial and perennial species.
Conclusions:
- Variability in seed settling velocity among species suggests diverse dispersal strategies linked to life history and ecological traits.
- Intraspecific variation in settling velocity may function as a risk-spreading mechanism for plants.
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