Anatomy of the Arabidopsis Root Tip:

1
Anatomy of the Arabidopsis Root Tip The
architecture of the root of this model plant is
very simple (Fig. 1 below). Each of the tissues
outside the vascular bundle (the pericycle, the
endodermis, the cortex and the epidermis) are
only one cell layer thick.  The columella is
one of the gravity sensing organs of the plant.
C1-C4 below refer to specific cells in the
columella. The QC is the quiescent center.
Quiescent means quiet, referring to the fact that
these cells seldom divide. The cells next to the
QC do divide frequently and are the stem cells of
the root. The cells above the QC give rise to
the epidermis, cortex, endodermis, pericycle and
the vascular bundle. The cells below the QC give
rise to the root cap, including the columella. 

• Zone of

Zone of differentiation
Zone of elongation
Zone of cell division
Figure 2. Detection of GUS expression in an
LHA2GUS line
Figure 1. Tissues of the Arabidopsis root