Abstract
There is a world-wide effort to reduce the amount of chemicals used in crop production by introducing modern biological and ecological methods. One possible alternative is allelopathy. A laboratory trial was carried out to investigate of alleopathic potential of Angelica . In this study the effect of different concentrations of aqueous extract of Angelica herb was investigated on seed germination percentage and rate of Upland Cress (Lepidium sativum) and Radish (Raphanus sativus L.). The trial was carried out in completely randomized design with four replicates. Seven treatments (aqueous extract including 10, 20, 30, 50, 70, 100% and distilled water as a control treatment) were applied on Upland Cress seeds and five treatments (water extract including 30, 50, 70, 100% and distilled water as control) were applied on Radish seeds. The results revealed that treatment of Upland Cress seeds with 50, 70 and 100% aqueous extract significantly decreased percent and rate of seed germination. In Radish, treatment of seeds with 70 and 100% aqueous extract resulted in the least percent of seed germination and treatment of seeds with 50, 70 and 100% aqueous extract resulted in the least rate of seed germination. Overall results showed that with increasing the applied extract concentration, seed germination percentage and rate significantly decreased.

Keywords: Allelopathy, Angelica archangelica, Aqueous extract, Raphanus sativus, Lepidium sativum