Germination and seedling growth of barley as affected by Artemisia annua water extract

Laboratory and greenhouse pot experiments were conducted to assess the allelopathic effects of Artemisia annua water extract on germination and growth of barley. Lower concentrations of A. annua water extract (0.5 and 1.0 %) did not affect the germination of barley seeds. However, higher concentrations (1.5-3.5 %) resulted in significant reductions in the germination percentage. Seedling growth of barley was also affected by A. annua water extract. Both shoot and root lengths were negatively affected by A. annua water extract and the degree of inhibition was concentration dependent. When barley seedlings were subjected to 0.5% extract concentration, shoot length was inhibited by 6% while root length showed 18.5% inhibition over control seedlings. The lowest shoot and root lengths were recorded at 3.0 and 3.5 % water extract. At 0.5 % extract concentration, shoot and root fresh and dry weights were significantly unaffected compared with the control. Shoot fresh weight was significantly unaltered when seedlings were treated with 1.0 % extract. However, at the same concentration root fresh weight, shoot dry weight, and root dry weight were inhibited by 44.7, 33.3, and 40 %, respectively. The present results confirmed that root growth (length and weight) was more sensitive to A. annua water extract than shoot growth. The present results also indicated the presence of water soluble allelochemicals in A. annua that are able to inhibit growth of barley.