Breaking of Dormancy in Xanthium Seeds by Kinetin Mediated by Light and DNA-dependent RNA Synthesis

Kinetin was able to break the dormancy of the “upper seed” (in bur) of Xanthium by antagonizing the endogenous inhibitor present in the embryo. Other growth substances like indoleacetic acid, gibberellic acid and cycocel were without effect. Breaking of dormancy by kinetin was dependent on reversible phytochrome system and DNA-dependent RNA synthesis. Protein synthesis is possibly not involved in the act of dormancy breaking. Endogenous inhibitor possibly participates in the mechanism of repression of genie site(s). It is suggested that an interplay of endogenous inhibitors, kinins and other factors (light, temperature, etc.) regulate dormancy, germination and differentiation by repression and derepression of DNA sites.