Remarkably, the dormancy status could vary even within a species, depending upon the factors such as differences between individuals, location, climatic conditions as well as nature and duration of seed storageafter collection. Apparently, seed dormancy is of immense significance in ensuring the survival of plant species during adverse conditions. However, it hampers the seed germination that turns out to be a disadvantage for the seed based propagation/cultivation of plant species. The full realization of the potential of seeds in achieving plant regeneration/cultivation of a plant species depends to a great extent on the understanding of the basic mechanism(s) of dormancy. In the present study, the presence ofgermination/chemical inhibitors in the dormant seeds of important plant species namely, Aconitum heterophyllum from Kinnaur (Himachal Pradesh) has been determined by monitoring the effect of leachate and extract of dormant seeds on germination of seeds of a phytometer species namely, Brassica juncea.Due to the treatment with the seed leachate of freshly harvested, 1, 2 and 3 year stored seeds of A. heterophyllum, a45, 36, 25 and 23% inhibition of B. junceaseed germination was evident. Similar observations were obtained with seed extract with some quantitative differences. The findings reveal the presence of chemical inhibitors involved in seed dormancy regulation of concerned plant species. Remarkably, there appeared a loss of inhibitors with storage ofseeds as revealed by the reduction in the degree of inhibition of B. junceaseeds.