DRY-MATTER PARTITIONING IN A TOMATO PLANT - ONE COMMON ASSIMILATE POOL

The influence of the distance (transport resistance) between source and sink on dry matter distribution between fruits and vegetative parts in tomato was studied. In two glasshouse experiments, a control treatment (single-shoot plants, no truss removal) was conducted, together with two double-shoot treatments: double-shoot plants with no trusses removed from one shoot and all trusses removed at anthesis from the other shoot (100-0) and double-shoot plants with every second truss removed from both shoots (50-50). Plant growth and dry matter distribution was recorded by periodical destructive harvests, during a period of about 100 d after anthesis of the first truss. In Experiment 2, plants were probably sink-limited. At the end of both experiments, 58-60% of dry matter was in the fruits for control plants, whereas for both double-shoot treatments this was 43% (Experiment 1) or 38% (Experiment 2). Until 60-65 d after first flowering, vegetative growth of the individual shoots in both double-shoot treatments was the same. Results supported the assumption of one common assimilate pool and showed no significant influence of distance (transport resistance) between source and sink on dry matter partitioning.