The structural anatomy of the abscission zone in the "knuckle" of the pedicel supporting the tomato fruit may provide an explanation as to how and why a fruit such as a tomato (Lycopersicon esculentum) can accumulate both water and dry matter. There is a significant reduction in xylem and a major increase in phloem cross-sectional area through the knuckle relative to the rest of the pedicel that persists from flowering through to fruit maturity. This will produce a site of high resistance to water flow in the xylem and transfer the demand for water by the fruit to the phloem, thus linking water and dry matter influx into the fruit. Transpiration from the fruit will play a role in initiating or maintaining the flow of phloem sap to the fruit.