Synergistic inhibition of kale seed germination by coumarin and (2-chloroethyl)-trimethylammonium chloride, and its reversal by kinetin and gibberellic acid.

1. The retarding effect of (2-chloroethyl)trimethylammonium chloride (CCC) on germination of kale seeds is reduced and overcome by either kinetin or gibberellic acid (GA). 2. Coumarin inhibition of germination is reduced by kinetin but not by GA. 3. Germination of seeds treated with coumarin in combination with CCC is blocked; both kinetin and GA reduce the synergistic, inhibitory effect of coumarin and CCC. It is suggested that coumarin and CCC block alternative metabolic pathways which lead to germination in kale seed; these pathways are directly controlled by kinetin.