The plant root is the organ in vascular plants that normally lies beneath the surface of the soil. Although this is not always the case as there are structures known as aerial roots that grow above the ground or aerating roots that grow above the ground or water.

The  plant root is defined as the plant body that has no leaves and nodes and serves as the plants foundation beneath the soil.

The Radicle is the embryonic root that first emerges from the plant seed.

Plant roots

Plant roots photograph by Qf8.

Plant Root Function

There are four major plant root functions:

  1. Responsible for absorbing water and other nutrients in the soil

  2. Anchors the plant to the soil or ground

  3. Serves as storage of nutrients and food of plants

  4. Helps prevent soil erosion

Roots also have the ability to synthesis cytokinin, in response to the concentration of nutrients that act as signals that determine how fast shoots can grow.

Plant Root development

The primary root develops from a radicle and will become the taproot, which is the dominant root. The roots that will grow from other roots are termed as the lateral roots and adventitious roots are those that arise from the organs of plants such as in the leaves or stems.

The taproot system is the process wherein the primary root becomes the plant’s central roots with minimal branching that consists of smaller and secondary lateral roots. This system is present in dicot plants and it actually one of the key distinguishing characteristics between dicots  and monocot plants;  who are known to have fibrous roots.

In plants that have a taproot system, the primary root that looks like a trunk develops directly from the radicle and will grow downwards in the soil. The lateral roots will soon grow from the taproot, which can initially grow horizontally. As the roots grow, the root cap will be pushed forward, probing the soil while absorbing nutrients and water mainly through the fine root hairs.

In monocot plants such as grasses, the plant root system is known to be a fibrous root system. This plant root system does not have a single taproot due to the death of the embryonic root back when the plant was still young. Instead there will be a dense mass of slender and somewhat adventitious roots that grows from the tip of the stem down to the soil, branching repeatedly and forming a mass of fine roots.

©2005-2015 Plant Biology Advice - Dean Ravenscroft