Effects of aqueous extracts from Artemisia afra parts and soil on seed germination and early seedling development in selected plant species

Aqueous extracts from leaves, stems, roots of the aromatic shrub Artemisia afra and soil on which Artemisia was grown, were used to investigate their inhibitory effects on germination and seedling development of maize (Zea mays), bean (Phaseolus vulgaris) and ryegrass (Lolium perenne). Dilutions of 1:1,1:2.5 and 1:5 v/v of the original extracts were prepared by adding deionised water to the original (undiluted) extracts. Deionised water and extracts from soil on which A. afra had never grown were used as controls. Extracts from A. afra soil and plant parts significantly (p < 0.05) reduced seed germination, height and dry matter of all the seedlings compared with the controls. However, as the dilution of the original extracts increased, there was a significant increase in seed germination and dry matter yields. This observation was consistent in all the plant species indicating that there was reduction in the concentration of the compounds inhibiting germination and seedling growth. The inhibitory effects ...