Everything Life Sciences Grade 10

produce new cells. In addition to mitosis, newly divided cells undergo elongation in the
same direction of root lengthening.

Figure 6.5: Primary and secondary root system of a cotton plant

Above the region of cell elongation, thousands of tinyroot hairsare found in the root hair
region. The function of the root hairs is to absorb water and dissolved mineral salts from the
soil. As the root grows, it thickens and may producelateral rootsin the mature region as
shown in Figure 6.6.

Figure 6.6: The dicotyledonous root

There are two major types of root system.

1.Taproot system: root system comprising one primary root and many secondary roots

branching off the primary root. Examples of taproots include carrot and beetroots

where the roots serve a storage function. Tap roots are found in dicotyledonous plants.

2.Fibrous root system: system with no dominant primary root but many secondary roots

of similar size. Fibrous (adventitious) root systems are common in monocotyledons.

Examples include coconuts and grasses.

Tissue distribution in root

The different tissues in the root have a distribution which is common to all dicotyledonous
plants and is shown in Figure 6.7.

Chapter 6. Support and transport systems in plants 161