Effects of Soil Biota and rhizosphere Extract from Non-Native Lonicera maackii on the Natie Impatiens capensis

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Invasive plant species, such as Lonicera maackii, are threats to the ecosystems of their invaded ranges. While many plants species are identified as being invasive, little is known about the mechanisms that allow for their success. An area of specific interest is how a non-native invasive species can interact with a native plant species. Allelopathy is a proposed mechanism by which an invasive plant might directly, or indirectly, suppress a competitor by phytochemical products. Though L. maackii has been described as having allelopathic potential, it remains unclear as to the impact that it has on below ground processes. These processes may include nutrient uptake, mycorrhizal infection, soil microbial activities and response to pathogens. In order to explore the potential below ground effects of L. maackii on a native species, Impatiens capensis, we tested the effects of a rhizosphere extract under two soil conditions and measured mycorrhizal infection, through time, with microscopy. The natural fluorescence of the mycorrhizae allowed us to observe changes in the infection of the roots resulting from treatment with L. maackii rhizosphere extract. Our results found that soil sterilization, and soil sterilization with exposure to L. maackii, affect mycorrhizal infection in I. capensis roots. In addition, we found positive effects of soil sterilization on above ground growth measures. Evaluation of our growth measures and mycorrhizal infection revealed different positive correlations between various growth measures in different treatments, but no significant correlations to mycorrhizal infection. The results of this experiment offer supporting evidence of the allelopathic potential of L. maackii, as well as the significant role of the microbial community present in field soils for plant-plant interactions and early growth performance


Poster presentation at the 2013 FLEPPC/SE-EPPC Joint Annual Symposium, Panama City Beach, FL.