Comparing Allelopathic Effects of Root and Leaf Extracts of Invasive Alliaria petiolata, Lonicera maackii and Ranunculus ficaria on Germination of Three Native Woodland Plants

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Invasive plant species can exhibit allelopathic effects on native plant species. The strength of this allelopathic effect can vary with invasive species, with target species and with type of plant tissue extract. The purpose of this study was to determine the direct effects of extracts from roots or leaves of three Midwestern US invasive plants (Alliaria petiolata, Lonicera maackii and Ranunculus ficaria) on the germination success of three native target species (Anemone virginiana, Blephilia hirsuta and Elymus hystrix) in a fully factorial experiment. Leaf extract treatments overall showed more germination inhibition compared to root extract treatments. As concentration increased, effects of extracts increased. Extracts of leaves of A. petiolata had the greatest inhibition of germination across all other treatments. Effects of root and leaf extracts of each invasive species varied with each target species. While E. hystrix showed little response to extracts of roots or leaves of L. maackii and R. ficaria, B. hirsuta and A. virginiana germination were reduced by leaf extracts of these two invasive species. This study confirms the strong direct allelopathic effects of A. petiolata, though the strength of the effect varies with target species and with type of tissue used to make extracts. This study is the first to directly compare the effects of these invasive species on a suite of native, ecologically-relevant target species.


Author Institution: Department of Biology, Wilmington College, Wilmington, Ohio



The Ohio Journal of Science, v112, n2 (2013), 37-43.