Tap Root System

Definition of Tap Root System

A single dominant root developing from the radical of the embryo vertically underground the soil.

The plant root system generally grows vertically downwards under the ground
It is a single prominent root and is also known as main root or primary root
It is persistent, i.e. it is retained throughout the life time of the plant
The germination of the seed gives rise to the first root
This root is known as radical
Tap root system develops from this radical
The primary root gives off many lateral branches known as secondary roots
These secondary roots further branch to give rise to tertiary roots
Terttiary roots further branch into rootlets and they bear root hairs for absorption
The tap root generally grows deep down inside the soil, when compared to the fibrous roots
It is mostly found in conifers and Dicotyledonous plants
Most of the tap roots are generally modified roots, which serve as storage (carbohydrates, generally starch) organs
The tap roots are categorised into four types depending upon their modification as follows:
- a) Conical: The shape of root is like cone wide at the top end and tapering towards the bottom end. Example: Carrot
  b) Fusiform: The root is widest at the middle when compared to the tapering ends at top and the bottom like a spindle. Example: Radish
  c) Napiform: The root is more or less spherical, broadest at the top and a small and very thin at the bottom. Example: Turnip
  d) Tuberous: The root is thick and fleshy with no definite shape. Example: Cassava, Mirabilis
It is difficult to uproot the tap root when compared to the fibrous roots