University of Minnesota College of Biological Sciences researcher Helene Muller-Landau has developed a new theory explaining why some plant species produce a small number of large seeds while others produce a large number of small seeds.
Using mathematical modeling, Muller-Landau demonstrated that plants having different size seeds can coexist when regeneration sites vary in stressfulness. Species that produce large seeds (e.g., coconuts) have the advantage under stressful conditions -- such as drought or shade -- while plants that produce large numbers of small seeds (e.g., fig species) have the advantage in areas with adequate water and light.
The research was published in the Early Online edition of Proceedings of the National Academy of Sciences during this week of Feb. 15. To read the research paper, visit http://www.pnas.org/content/early/2010/02/11/0911637107.full.pdf+html
"The standard explanation has been that big seeds beat out small seeds under all conditions, but that's not necessarily true," Muller-Landau says. "Big seeds have the advantage in stressful conditions and small seeds have the advantage when sun and water are abundant. It's a trade-off between tolerance and fecundity."
Muller-Landau's "tolerance-fecundity model" explains why different plant species have different size seeds and may also provide insight into the variation of the number and size of offspring among animal species, she says. It also helps to explain why there's so much diversity among species, a key finding that advances understanding of evolutionary biology.
As a staff scientist at the Smithsonian Tropical Research Institute and head of an international effort to quantify carbon in forests worldwide, Muller-Landau has visited forests in China, Malaysia, Ecuador and Panama, among other exotic destinations. Her experience has enabled her
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| Contact: Patty Mattern mattern@umn.edu 612-624-2801 University of Minnesota Source:Eurekalert |