Anesthetic Effects on Secondary Dormancy and Phytochrome Responses in Setaria faberi Seeds

Abstract

Seeds of giant foxtail (Setaria faberi Herm.) entered secondary dormancy after pretreatment in H₂O at 35°C. Pretreatment in 0.1 m ethanol, or several other substances with anesthetic properties, prevented secondary dormancy induction. Pretreatment in 0.5 m ethanol inhibited germination in darkness, but germination could be stimulated by a red irradiation. Germination was initially insensitive to light. Two separate responses are indicated. The first, affected by a variety of substances and low (0.1 m or less) concentrations of ethanol, is related to anesthetic effects and prevention of secondary dormancy. The second, induction of response to red irradiation, is caused by 0.5 m ethanol and some closely related substances. The anesthetic effect is accomplished within the first 8 hours of imbibition while the phytochrome induction effect required treatment for more than 24 hours. Both responses were lost if the 35°C imbibition began in H₂O. Involvement of cell membranes is suggested in the prevention of secondary dormancy by anesthetics.