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

The influence of the distance (transport resistance) between source an d sink on dry matter distribution between fruits and vegetative parts in tomato was studied. In two glasshouse experiments, a control treatm ent (single-shoot plants, no truss removal) was conducted, together wi th two double-shoot treatments: double-shoot plants with no trusses re moved from one shoot and all trusses removed at anthesis from the othe r shoot (100-0) and double-shoot plants with every second truss remove d from both shoots (50-50). Plant growth and dry matter distribution w as recorded by periodical destructive harvests, during a period of abo ut 100 d after anthesis of the first truss. In Experiment 2, plants we re probably sink-limited. At the end of both experiments, 58-60% of dr y matter was in the fruits for control plants, whereas for both double -shoot treatments this was 43% (Experiment 1) or 38% (Experiment 2). U ntil 60-65 d after first flowering, vegetative growth of the individua l shoots in both double-shoot treatments was the same. Results support ed the assumption of one common assimilate pool and showed no signific ant influence of distance (transport resistance) between source and si nk on dry matter partitioning.