Selenomethionine as a dormancy-breaking agent in seeds of Stylosanthes humilis

Physiological dormancy of scarified seeds of Townsville stylo (Stylosanthes humilis H.B.K.) was released by seleno-L-methionine (SeM), but not by L-me thionine. This regulating effect was impaired by inhibitors of ethylene bio synthesis and action; in the first case SeM action was restored by 2-chloro -ethylphosphonic acid (CEPA) and 1-an-aminocyclopropane-1-carboxylic acid ( ACC). The Se-aminoacid proved to be toxic in a time-dependent manner to see dling growth, inhibiting primarily the hypocotyl expansion. This toxicity i s suggested to trigger ethylene biosynthesis, which would promote germinati on of dormant seeds.