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Translocation: Pressure-Flow in Phloem

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Translocation moves sugar from source tissues, where photosynthate forms, to sink tissues, where it is used or stored, via pressure-driven phloem flow.

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Sucrose loading at a source lowers phloem water potential, drawing xylem water in and generating pressure that pushes sap toward the sink.

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Unlike xylem flow, which runs only upward, phloem flow runs either direction, depending on the nearest sink's location.