Lesson 7 of 15
Tubes for water and food
Show on a big screenAn animal peels bark off all round a tree trunk. Bark is the outer covering of a trunk. Which tube is cut?
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Step 1 of 3
- Two tissues run side by side up the stem.
- Xylem carries water upward. Phloem carries food from the leaves.
- Peel a ring of bark, over the phloem, and food stops there.
The phloem is cut, because it lies just under the bark.
Rule
Xylem carries water and minerals up from the roots. Phloem carries food from the leaves to other parts.
- Xylem — water tubes. Most of its cells are dead. It also gives strength.
- Phloem — food tubes. Most of its cells are alive.
The bark covers the phloem. The xylem lies deeper inside.
Take off a ring of bark. The phloem is cut there, so food cannot pass. The xylem is not cut, so water still rises.
Try the lab to finish this lesson.