Sylvain, Iman , McKenna, Mary .
Comparison of Seedling Fitness in the Hyperaccumulator, Alyssum murale Waldst and Kit. (Brassicaceae) in Soils With and Without Nickel.
The role of edaphic factors in endemism and competitive ability of serpentine species has long been of interest to plant ecologists. Alyssum murale Waldst and Kit. (Brassicaceae) is a nickel-hyperaccumulator plant originating on serpentine soils in the Mediterranean region. Although this species grows on serpentine and non serpentine soils, little is known about its ecological response to soil nickel. Since Alyssum murale has been introduced for phytoremediation of nickeliferous soils in North America, it is particularly important to understand how soil nickel influences its critical life history parameters. This study examined the effect of seed origin, soil type, and seed weight on growth and survivorship of A. murale seedlings. Seeds from plants grown with or without nickel were individually weighed and planted singly in 2 inČ plastic cells containing pure Sunshine mix or Sunshine mix amended with 500 ppm nickel (1:1 Ni acetate: Ni sulfate). Effects of seed origin and soil type were compared by two-way ANOVA with seed weight as a covariate. Seeds produced by plants grown in soil with nickel had significantly greater seed weight (p=0.020), germination percentage (p=0.000) and shoot weight (p=0.009). Seed weight had a positive effect on germination (p=0.000), leaf number (p=0.026), shoot weight (p=0.042) and root weight (p=0.008) after six weeks. Although A. murale germinated equally well on soil with and without nickel, seedlings grown in soil with nickel had greater numbers of leaves (p =0.000), shoot biomass (p=0.000) and root biomass (p=0.000) after six weeks. The strong positive growth response in the presence of nickel combined with the seed weight advantage of offspring originating on nickel soils, suggests nickel plays a powerful role in influencing seedling fitness in A. murale. This positive response to soil nickel may influence the colonization patterns and competitive ability of Alyssum murale on serpentine and non-serpentine soils.
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1 - Howard University, Biology Department, 415 College St NW, Washington, DC, 20059, USA
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM