Characteristics of the inhibitory action of 1,1-dimethyl-4-(phenylsulfonyl)semicarbazide (DPSS) on ethylene production in carnation (Dianthus caryophyllus L.) flowers

1,1-Dimethyl-4-(phenylsulfonyl)semicarbazide (DPSS) inhibited ethylene production in carnation flowers during natural senescence, but did not inhibit the ethylene production induced by exogenous ethylene in carnation flowers, by indole-3-acetic acid (IAA) in mungbean hypocotyl segments and by wounding in winter squash mesocarp tissue. These findings suggested that DPSS does not directly inhibit ethylene biosynthesis from L-methionine to ethylene via S-adenosyl-L-methionine and 1-aminocyclopropane-1-carboxylate. During natural senescence of carnation flowers, abscisic acid (ABA) was accumulated in the pistil and petals 2 days before the onset of ethylene production in the flower, and the ABA content remained elevated until the onset of ethylene production. Application of exogenous ABA to cut flowers from the cut stem end caused a rapid increase in the ABA content in flower tissues and promoted ethylene production in the flowers. These results were in agreement with the previous proposal that ABA plays a crucial role in the induction of ethylene production during natural senescence in carnation flowers. DPSS prevented the accumulation of ABA in both the pistil and petals, suggesting that DPSS exerted its inhibitory action on ethylene production in naturally-senescing carnation flowers through the effect on the ABA-related process.