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 productionin carnation flowers during natural senescence, butdid not inhibit the ethyleneproduction induced by exogenous ethylene in carnationflowers, by indole-3-acetic acid (IAA) in mungbean hypocotylsegments and by wounding in winter squashmesocarp tissue. These findings suggested that DPSSdoes not directly inhibit ethylene biosynthesis fromL-methionine to ethylenevia S-adenosyl-L-methionine and1-aminocyclopropane-1-carboxylate. During naturalsenescence of carnation flowers, abscisic acid (ABA)was accumulated in the pistil and petals 2 days beforethe onset of ethylene production in the flower, andthe ABA content remained elevated until the onset ofethylene production. Application of exogenousABA to cut flowers from the cut stem end caused arapid increase in the ABA content in flower tissuesand promoted ethylene production in the flowers. These results were in agreement with the previousproposal that ABA plays a crucial role in theinduction of ethylene production during natural senescence incarnation flowers. DPSS preventedthe accumulation of ABA in both the pistil and petals,suggesting that DPSS exerted its inhibitory action onethylene production in naturally-senescing carnationflowers through the effect on the ABA-related process.