Practice question

Quiescent center of Arabidopsis root tip consists of four to seven cells characterized by extremely slow division rate, highly oxidized redox environment, condensed chromatin, and enriched expression of WOX5, QC25, QC46 markers, and elevated auxin signaling reporters. These rarely dividing organizer cells protect genomic integrity while preventing differentiation of surrounding initial cells through short-range mobile signals involving WOX5 and CLE40-CLV1 peptides. Upon severe wounding or stem cell ablation, QC cells rapidly re-enter cell cycle replenishing lost initials, revealing protective quiescence mechanism enabling reservoir function for regeneration and continuous root growth.