Wilmington College, Wilmington, OH, 45177, USA
1 Correspondence author, Current address: US Forest Service, 17147 E. Hwy 40, Silver Springs, FL 34488 USA. E. Mail :KAL143@alumni.psu.edu
2 Current address: 4321 Crestline Rd., Bucyrus, OH 44820 USA.
Online published on 12 March, 2012.
Garlic mustard (Alliaria petiolata), Amur honeysuckle (Lonicera maackii) and lesser celandine (Ranunculus ficaria) are three invasive species in US Midwestern forests. The comparative allelopathic effects of leaf extracts of these species on germination and reproduction of Arabidopsis thaliana were investigated in a growth room. Highest extract concentrations (0.3 and 0.2 g fresh leaf tissue/mL distilled water) of L. maackii delayed germination in potting soil compared to the control. Extracts of L. maackii also decreased the number of siliques in potting soil compared to the control and to A. petiolata extracts, with extracts of R. ficaria having intermediate effects. In field soil, extracts of L. maackii and R. ficaria significantly decreased the number of siliques compared to extracts of A. petiolata. In a third experiment, effects on germination of three agricultural species (Brassica oleracea, Lactuca sativa and Ocimum basilicum), were studied. Ranunculus ficaria and L. maackii extracts were least harmful to germination, while A. petiolata extracts were most harmful. Germination of L. sativa and O. basilicum was more sensitive to A. petiolata and R. ficaria extracts, while germination of B. oleracea was more sensitive to L. maackii extracts. These results showed differential allelopathic effects of these invasive species, which varied with test species and experimental conditions.
Alliaria petiolata, Arabidopsis thaliana, Brassica oleracea, Exotic species, Fig buttercup, Germination inhibition, Lactuca sativa, Leaf extracts, Lonicera maackii, Ocimum basilicum, Phytotoxicity, Ranunculus ficaria
