Some Studies of Coumarin and Coumarin Analogues as Germination Inhibitors of Radish Seeds

1. The effect of coumarin and eight coumarin analogues upon radish seed germination was studied. Coumarin itself is a much more effective inhibitor than are the other compounds examined. 2. There appears to be a threshold concentration for normal seedling development in the region of 10-3 M coumarin. 3. Plant metabolites such as octanoate, sucrose, glutathione, and calcium pantothenate do not appear able to reverse the coumarin inhibition of radish-seed germination when present in 10-3 M concentration and in the presence of a similar concentration of coumarin.