Protophloem definitions

Protophloem

The conductive tissue of actively growing parts of the plant. Its sieve tubes function for a brief period, and are replaced by metaphloem elements.
Found on http://www.encyclo.co.uk/visitor-contributions.php

---

protophloem

the part of the primary phloem that develops first, consisting of narrow, thin-walled cells.
Found on https://www.infoplease.com/dictionary/protophloem

---