Abstract
The roles of free and bound abscisic acid (ABA) in the breaking of dormancy in seeds of peach (Prunus persica (L.) Batsch) were investigated. Concentrations were consistently 10- to 100-fold higher in the embryonic axes of seeds than in the seed coats or cotyledons. Free and bound ABA declined 75 to 95% during stratification at both 5° and 20°C, yet only the 5° treatment broke dormancy. Extracts of chilled seeds were less inhibitory to germination of non-dormant seeds than were extracts of non-chilled seeds, but ABA content of the extracts was sufficient to account for only a small part of their biological activity.