Recent Topics Posters
Stallworth, Brittany , McKenna, Mary .
Interactions between fungi and the Ni-hyperaccumulator, Alyssum murale.
Alyssum murale Waldst and Kit. (Brassicaceae) is a nickel hyperaccumulator found on serpentine and non-serpentine soils in the Mediterranean region. Serpentine soils present many challenges for plants including high levels of toxic metals (Ni, Cr), a low Ca/Mg ratio, and low soil fertility. A greenhouse experiment was designed to explore the possibility that soil nickel concentration influences resistance to fungal pathogens. A. murale plants grown in soil nickel levels ranging from 0 ppm ΓΆ€“2000 ppm were inoculated by brushing finely ground fungal tissue liberally over the entire shoot system. Response to infection was measured by comparing leaf number, shoot weight, and root weight after two weeks. Plants in high nickel soils (500 ppm and 2000 ppm) had significantly more leaves and greater shoot biomass than plants in low nickel soils (0 ppm and 50 ppm). Greater shoot growth in plants from high nickel soils suggests that elevated soil nickel levels may contribute to pathogen resistance in this species. Root weight did not differ significantly between plants in different nickel levels, however. We also compared growth (leaf number) in A. murale plants with and without mycorrhizal inoculation (BioOrganics Endomycorrhizae Inoculant). In soil without added nickel (0 ppm), plants with mycorrhizae were significantly smaller than plantswithout mycorrhizae. In soil with added nickel at all levels (100, 500, 2000 ppm), plant size did not differ in the presence or absence of mycorrhizae. Further studies are underway to stain and observe AM fungal colonization of A. murale roots. Negative effects of mycorrhizal associations can occur if plants are supplying energy to the fungus without gaining substantial benefit. Since the native range of A. murale includes edaphic environments with varying nickel concentrations, these observed differences in pathogen resistance and responses to the presence or absence of mycorrhizae may influence establishment and maintenance of populations.
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1 - Howard University, Biology, 415 College St NW, Washington, DC, 20059, USA
2 - HOWARD UNIVERSITY, Biology Department, 415 College St. N.W., Washington, DC, 20059, USA
soil edaphic factors
Presentation Type: Recent Topics Poster
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM