Cytokinins in cut carnations. X. The effect of stem length and holding time on the transport and metabolism of [8-14C]6-(benzylamino)purine

Stem length and to a lesser extent holding time influenced the transport of 8-¹⁴C]6-(benzylamino)purine (BA) within the carnation flower ( Dianthus caryophyllus L.). A stem length of 40 cm as compared to one of 10 cm resulted in a lower amount of BA reaching the carnation flower head when the flowers were held in solution for 3 to 24 h. There was also a slight delay in cytokinin movement from, as well as increased metabolism within, the stem tissues. Consequently levels of radioactivity and the nature of metabolites produced in the upper floral components were influenced by movement through the stem. In the flower head the receptacle was the strongest sink for flowers with 10 cm stem lengths. A metabolite tentatively identified as ribosyl-benzylaminopurine 9R]BA was the major compound formed in all flower components. This metabolic step appeared to be reversible. Various minor stable metabolites and possible breakdown products were also produced.