The mobility of different ionic forms of silver ((110m)Ag) has been studied using semiconductor radiation detectors. Silver, applied as silvernitrate (2mM), moves upward in the stems of cut carnations (Dianthus caryophyllus L.) at about 3 cm day(-1). This transport has the characteristics of a chromatographic exchange transport, but is not promoted by the addition of other cations (K(+) or Ca(2+)). The silverthiosulphate anionic complex is transported at the same speed as [(32)P]phosphate (about 2 m h(-1)); orders of magnitude faster than Ag(+). The antiethylene action of silver is preserved in this complex, as shown by a significant improvement of the longevity of carnation flowers in the presence or absence of ethephon, even after a short treatment with the silverthiosulphate complex. Analysis of the silver content of different flower parts after a silverthiosulphate treatment shows a distinct accumulation in the receptacle, possibly associated with the antiethylene action.