protoxylem

views updated Jun 27 2018

protoxylem The primary xylem tissue that is formed in the expanding region of roots and shoots before the shoot or root has completed the elongation process. In the secondary walls of these vessels the lignin is deposited in rings and spirals, which allows for further elongation. The protoxylem is succeeded by metaxylem.

protoxylem

views updated May 23 2018

protoxylem The first xylem elements to form from the procambium.