noun Botany.

the part of the primary phloem that develops first, consisting of narrow, thin-walled cells.

Origin of protophloem

First recorded in 1880–85; proto- + phloem Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Science definitions for protophloem



The first formed phloem that differentiates from the procambium.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.