Articles
THE SEASONAL DISTRIBUTION OF 14C-LABELLED PHOTOSYNTHATES IN SOUR CHERRY (PRUNUS CERASUS)
Individual shoots consisting of the new extension shoot and a section of previous years fruiting wood were labelled with 14C four times during fruit development.
Only the soluble 14C fraction was monitored.
On the day of labelling a high activity was found in the soluble fraction with almost 90 % remaining in the leaves.
Two days after labelling approx. 75 % of the soluble activity had been translocated out of the leaves, regardless of the developmental stage.
During early fruit growth approx. 30 % of the absorbed radioactivity was transported into the soluble parts of the fruits.
In contrast, only 10 % of the absorbed activity was recovered in the fruits two days after labelling in mid June.
Apparently, cell wall and endocarp development were the dominating sinks at this stage.
In mid July translocation to soluble parts of the fruits again became significant and in August, during final fruit ripening, 80 % of the absorbed activity was recovered as soluble solids in the fruits two days after labelling; all the absorbed activity was recovered in fruits and other parts two days later.
The fruits closest to the extension shoot attracted the higher proportion of the labelled assimilates.