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In this video, we look at translocation in the phloem. First we explore what is meant by a source and a sink. We then explore how active loading of sucrose into the phloem takes place in the source and how this leads to mass flow of assimilates in the phloem. Finally, we look at the evidence for this active model of translocation.

Image credits:

Leaf with sun

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Govindaraj Mahalakshmi, CC BYSA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Potato Plant
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Arg12730, CC BYSA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Roots
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Rosser1954, CC BYSA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Shoot

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sakura from between places, CC BY 2.0 https://creativecommons.org/licenses/..., via Wikimedia Commons