Tomato plants were grown in Spring and Fall in a non-heated greenhouse in order to investigate the effect of fruit position on dry matter distribution between vegetative organs and fruits. Treatments consisted of plants with one shoot (control) or two shoots per plant, with fruits located in both stems or only in the main stem. In each experiment, the same number of trusses was kept in all plants, by truss removal on the double-shoot plants. Thus, truss number per plant was eight in Spring and ten in Fall, while number of leaves per plant was respectively 27 and 37 in control plants and 52 and 65, on average, on the double-shoot plants. In Spring, mean fruit dry matter was 155g on double-shoot plants and 95g on control plants. In Fall, mean fruit dry matter accumulation was 99g in double-shoot and 78g in single-shoot plants and differences were not significant. In both seasons, no significant differences were recorded between double-shoot treatments, regardless of the position of fruits on the stem. In Fall, the fraction of total dry matter allocated to fruits was 0.40 in control and 0.24, on average, on the double-shoot plants, suggesting sink strength of fruits was affected by low temperatures. It was concluded that fruit position do not affect dry matter distribution and results support the hypothesis of one common pool of assimilates circulating freely in the tomato plant.
Lycopersicon esculentum; growth; dry matter; partitioning of assimilates
