Pattern of C-14-assimilate distribution in chrysanthemum cv. Red Delano with particular reference to branch interrelations

The physiological organization of pinched plants of chrysanthemum was investigated by following the pattern of C-14-assimilate allocation from individual leaves on the main stem and uppermost branch, and from selected branches. In vegetative plants almost all of the assimilate imported by a developing branch was obtained from its subtending leaf and the three uppermost branches became virtually independent components of the plant within three weeks from pinching. The root system was the major sink for assimilate exported by main stem leaves and branches. Only a very small proportion of assimilate was distributed generally throughout the shoot and there was evidence that this followed a sectorial pattern. There was no interbranch exchange of assimilate. In flowering plants the flowers were the major sink for assimilate produced within the flowering branch. The results are discussed in relation to competition for assimilate between various plant components and in terms of the physiological status of branches.