In this research, probable allelopathic effects of Heliotrope were investigated on early growth of wheat and barley. Aqueous extracts of the plant at 5, 10, 15 and 20% concentrations were prepared from whole dried plants and distilled water was used as control. Results indicated that released allelochemicals from Heliotrope had inhibitory effects on germination and seedling growth of the test seeds when compared with the control. With increasing aqueous concentrations the inhibitory effects were severed and the highest concentration (20%) had maximum inhibitions on both traits. The results also revealed that the sensitivity of the plants to allelochemicals was different. Wheat was more tolerant than barley to the materials. The results also showed that the root growth was more susceptible than shoot growth under chemical stresses. Allelochemicals changed seed reserve remobilization rates. The weight of reserve mobilization and seed reserve depletion percentage decreased while seed reserve utilization efficiency improved. These findings suggest that the catabolism reactions are more susceptible to allelochemicals than anabolic reactions. It was concluded that Heliotrope had a powerful allelopathic effect on the early growth of the crop plants and the interference of Heliotrope was a species-specific phenomenon
