PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Effects of tree species on soil bacterial communities and positive feedback on Ailanthus altissima.
Kleiner, Karl*,1, Smith, Gwen1, 1 York College of Pennsylvania, York, PA
ABSTRACT- The invasiveness of tree-of-heaven (Ailanthus altissima) has been attributed to multiple factors: allelopathy, high reproductive output, clonal growth form, rapid growth rates and tolerance to a wide range of environmental conditions. The allelopathic agents in Ailanthus are well documented, but their mechanism has largely been attributed to phytotoxicity. In this experiment, we compared the influence of Ailanthus on soil bacterial communities with the influence of three other early successional tree species. We conducted a soil training experiment in which Ailanthus, yellow-poplar (Liriodendron tulipifera), black locust (Robinia pseudoacacia) and red maple (Acer rubrum) were grown in pots with a 2:2:1 sterile soil:peat:sterile perlite mix. We hypothesized that Ailanthus would exhibit greater positive feedback when grown in sterile soil inoculated with its own microbial community relative to soil inoculated with microbial communities from other plant species. Soil extracts were used to inoculate R2A agar plates and 92-well microtiter plates containing multiple carbon sources (Biolog gram negative and ECO MicroPlates) to assess bacterial communities. Black locust and tree-of-heaven had greater functional richness, lower functional evenness and greater functional diversity when compared to soil in which no trees had been planted (control). Indices of bacterial communities from yellow-poplar and red maple did not differ from control soil. Seeds of Ailanthus were germinated and grown in sterilized, pre-cultured soil, and sterile control soil inoculated with pre-cultured soil. Germination was lower and the biomass was greater in inoculated soil from all tree species tested compared to pre-cultured soil that was sterilized. These results suggest that a positive feedback effect on Ailanthus may not be due to a species-specific alteration of the soil biota, but a more generalized response.
Key words: Invasive, Ailanthus, soil, bacteria