Why do mature sieve tube elements depend on companion cells?
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Correct answer: They lack many organelles and do not have a nucleus at maturity
Mature sieve tube elements remain living but lose their nucleus and many organelles. Companion cells provide metabolic support and help regulate loading and unloading of sugars.
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More Phloem questions
- What are sieve plates in phloem?
- Which sugar is most commonly transported through phloem in many plants?
- Which term describes a plant region that supplies sugars to the phloem?
- Which of the following is an example of a phloem sink?
- According to the pressure-flow hypothesis, what creates pressure in the phloem near a source?
- In the pressure-flow model, what happens at a sink region?