Persistence, Uptake and Translocation of [14C]Ethephon (2-Chloroethyl Phosphonic Acid) in Perlette and Cardinal Grapevines

[14C]ethephon was applied to different organs of detached and intact shoots of some grapevine cultivars. Recovery of 14C-labelled compounds, 48 h after application indoors to detached leaves, was 53-61% of the amount applied. Recovery was between 58 and 72% of the amount applied 4 h earlier to different sites on young intact shoots of potted vines, in a greenhouse. Uptake of labelled compound was only 19-26% of the amount applied. Translocation of [14C]ethephon was very slight. Most of the applied labelled compound remained at the application sites for many hours. Translocation was mainly basipetal as confirmed also by autoradiography.