Roots have four primary functions:

  1. Anchorage – roots permeate the soil holding plant in one place for life.

  2. Storage – roots can store large amounts of energy reserves

  3. Conduction – roots transport water and dissolved nutrients to and from the shoot

  4. Absorption – roots absorb large amounts of water and dissolved minerals from the soil.

Most dicots have a taproot system consisting of a large taproot and smaller branch roots that maximise storage. Monocots have fibrous root systems consisting of similarly sized roots that maximise absorption. Adventitious roots form on organs(stem, leaves) other than roots, .

The tips of most roots are covered and protected by a thimble shaped root-cap. Cells of root caps can secrete large amounts of mucigel, a slimy substance containing sugars, enzymes, and amino acids. Mucigel protects the roots from drying out. It also may contain compounds that inhibit growth of other roots. Mucigel lubricates roots as they push between soil particles. Soil particles cling to mucigel, thereby increasing the root's contact with the soil. The water-absorbing properties of mucigel help maintain the continuity between roots and soil water. Mucigel makes it possible for minerals, along with water in the soil, to be better absorbed by roots.  The mucigel also feeds beneficial bacteria which colonise the rooting zone.

The subapical region of the root includes the zones of cell division , cell elongation(where the root cells swell allowing most of the physical growth), and cell maturation.

The epidermis surrounds the cortex, which has 3 layers:

  1. Hypodermis – protects the roots
  2. Parenchyma – tissue that stores reserves
  3. Endodermis – is lined with the Casparian strip, which diverts water and dissolved minerals into the cytoplasm of endodermal cells

The stele includes all of the tissues inside the cortex, including the pericycle and vascular tissues. The pericycle produces branch roots. The narrow zone of soil surrounding a root is called the rhizosphere. Many microbes live in and affect the rhizosphere.

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