Annals of Botany 39: 439-446, 1975
© 1975 Annals of Botany Company
RESEARCH-ARTICLE |
The Role of Phloem Transport in the Translocation of Sucrose Along the Stem of Carnation Cut Flowers
Glasshouse Crops Research Institute Littlehampton, Sussex, BN16 3PU
Received: 17 June 1974
The pathway and distribution of 14C-sugars in flower parts have been examined to find out in which tissue sugars are translocated in the stem of the cut carnation; 14C-sucrose or 14C-glucose was supplied at the base of the cut stem from a feeding solution and the localization and chemical nature of the carbon-14 recovered from flower parts were investigated. By reducing the rate of transpiration it was found that the uptake of feeding solution was also reduced, but the distribution of absorbed 14C-sucrose in the flower parts was different from that which would be expected if sucrose moved exclusively in the transpiration stream. Autoradiographs demonstrated that 14C absorbed from the feeding solution as 14C-sucrose appeared in both xylem and phloem but predominantly in the latter; girdling failed to stop the translocation of the absorbed 14C-sucrose. Results of experiments with 14C-sucrose and 14C-glucose showed that sucrose was the mobile sugar and that glucose was converted to sucrose before it was translocated. It was concluded that the translocation of sucrose absorbed from the feeding solution takes place both in xylem and phloem and is regulated by a mechanism involving the loading and translocation of sucrose in the phloem.