[Studies on the transport of caffeine in the coffee plant (Coffea arabica)].

Caffeine transport in small amounts from leaf to leaf was demonstrated by application of doubly-labelled caffeine. There was no translocation from the subtending leaves into the fruits, but heavy translocation from the pericaprp into the seed tissue could be shown. The results were confirmed by the analysis of grafts between caffeine-containing and caffeine-free species. The importance of the pericarp with respect to the caffeine content of the mature coffee bean is discussed.