Effects of Aqueous Artemisia Extracts and Volatile Substances on Germination of Selected Species

Abstract

The present study was done to determine the effects of Artemisia substances, both water-soluble and aromatic, on the germination of selected grassland species. Aqueous extracts of Artemisia tridentata litter inhibited germination of such species as Agropyron smithii, Euphorbia podperae, Hedeoma hispida, Parietaria pennsylvanica, and Thlaspi arvense. Aqueous extracts of A. tridentata and A. cana leaves inhibited germination of Achillea millefolium, Artemisia cana, A. tridentata, Bromus inermis, Chrysothamnus nauseosus, and Thlaspi arvense. Germination of these same six species was inhibited by volatile substances from leaves of A. tridentata and A. cana. Aqueous extracts of leaves of Artemisia tridentata, A. cana, A. absinthium, A. frigida, and A. dracunculus all inhibited germination of Haplopappus spinulosus and Thlaspi arvense. Germination of Echinacea pallida was inhibited by leaf extracts of all the Artemisias tested except A. dracunculus. Germination of Plantago patagonica was inhibited by leaf extracts of only A. tridentata and A. dracunculus. Germination of Stipa viridula and S. comata was stimulated by leaf extracts of A. frigida and A. dracunculus. Aqueous leaf extracts of A. absinthium strongly inhibited germination of Stipa comata, but stimulated germination of Stipa viridula. Germination of certain species, such as Lepidium virginicum, Rumex crispus, and R. occidentalis, were not at all inhibited by leaf extracts of any Artemisias tested. Results of this experiment suggest possible influences of Artemisia chemicals on species distributional patterns in Artemisia-dominated vegetation, though further studies are required to verify whether the influences are valid under field conditions.