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Figure 92.
(a) Tap root systems have a main root that grows down, while (b) fibrous root systems consist of 
many small roots
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6.2 Reading #2
: Root Growth and Anatomy 
Seed germination is the first stage of root growth. The root system is formed by the embryo's 
radicle when the plant embryo leaves the seed. The root cap, a structure unique to roots and distinct 
from all other plant structures, guards the tip of the root. The root cap needs to be replaced regularly 
because it is easily damaged as the root pushes through the soil. Three zones can be identified in the 
root tip: a cell division zone, an elongation zone, and a maturation and differentiation zone (Figure 
93). The root meristem's actively dividing cells make up the zone of cell division, which is located 
closest to the tip of the root. The newly formed cells grow longer in the zone of elongation, 
lengthening the root in the process. The zone of cell maturation, where the root cells start to separate 
into distinct cell types, starts at the first root hair. The first centimeter or so of the root tip contains all 
three zones. 
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(credit b: modification of work by “Austen Squarepants”/Flickr)

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Figure 93.
The zones of cell division, elongation, and maturation are visible in a longitudinal view of the 
root. The apical meristem is the site of cell division. 
 
The root's epidermis, an outer layer of cells, encircles the ground tissue and vascular tissue. 
The epidermis aids in absorption and offers protection. 
Root hairs
, which are extensions of root 
epidermal cells, increase the surface area of the root, greatly contributing to the absorption of water 
and minerals. The cortex and the pith are two areas that the ground tissue creates inside the root 
(Figure 94). Roots have more cortex than stems, but less pith. Cells that store products from 
photosynthesis are present in both regions. The pith is located between the center of the root and the 
vascular tissue, while the cortex is situated between the epidermis and the vascular tissue. 

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Figure 94.
In this light micrograph of a cross section of a wheat (Triticum) root, staining reveals various cell 
types. Phloem cells stain blue, xylem cells and exodermis sclerenchyma cells stain red. Some cell types have 
a black stain. The region inside the endodermis is known as the stele or vascular tissue (indicated by a green 
ring). Root hairs are visible outside the epidermis
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The vascular tissue in the root is arranged in the inner portion of the root, which is called the