Taproot

Taproot is an enlarged somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.

Plants with taproots are difficult to transplant. The presence of a taproot is why dandelions are hard to uproot — the top is pulled, but the long taproot stays in the ground, and re-sprouts.

A taproot system contrasts to a fibrous root system with many branched roots.

Most trees begin life with a taproot, but after one to a few years the main root system changes to a wide-spreading fibrous root system with mainly horizontal growing surface roots and only a few vertical, deep anchoring roots. A typical mature tree 30–50 m tall has a root system that extends horizontally in all directions as far as the tree is tall or more, but well over 95% of the roots are in the top 50 cm depth of soil.

Many taproots are modified into storage organs.

Some plants with taproots:

Burdock
Cannabis
Carrot
Dandelion
Green alkanet
Kudzu
Parsnip
Patterson's Curse
Poppy mallow
Sagebrush
Sturt's Desert Pea
Radish
Turnip
Welwitschia

Development

Taproots develop from the radicle of the seed, which forms the primary root. It produces branches called the secondary roots, and they in turn produce branches to form tertiary roots. These may further branch to form rootlets. Soil characteristics strongly influence the architecture of taproots. For example deep rich soils favour the development of vertical taproots in many oak species such as Quercus kelloggii, while clayey soils promote the growth of mulitple taproots.

Typical taproots

Conical root: this type root tuber is conical in shape, i.e. broad at the base and tapering gradually towards the apex: e.g. carrot.
Fusiform root: this root is swollen in the middle and tapers towards the base and the apex: e.g. radish.
Napiform root: the root has a top-like appearance. It is very broad at the base and tapers suddenly like a tail at the apex: e.g. turnip.

Translation of "Taproot"

Danish: Pælerod, German: Pfahlwurzel, Spanish: Raíz primaria, Esperanto: Pivotradiko, Ido: Paliso-radiko, Italian: Fittone, Dutch: Penwortel, Japanese: 直根性, Polish: Palowy system korzeniowy, Swedish: Pålrot.