Every sugar pipe cell in a flowering plant has a best buddy right next to it. Companion cells do the hard work their partner can't do alone.
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In flowering plants, sugar travels through long pipe cells called sieve tube cells. These pipe cells are alive, but they have no nucleus.
Right beside each one is a long, thin companion cell. It has a big nucleus and lots of energy makers. The two cells grow from the same parent cell, which splits in two. They are like twins!
Press Power up on the 3D model to light up the energy makers in the companion cell.
The two cells are joined by many tiny tunnels through their walls. Through these tunnels, the companion cell sends its partner the things it needs to stay alive.
In many plants, companion cells also help load sugar into the pipe. They use energy to push sugar in, and then the sap carries it to roots, fruits, and new leaves.
Press Load sugar to watch sugar move from the companion cell into the sugar pipe.
When the companion cell stops working, its sieve tube partner stops working too. They really can't live without each other!