Taproot

The dandelion's taproot, quite apparent in this drawing, renders this plant very difficult to uproot – the plant itself gives way, but the root stays in the ground and may sprout again.

A taproot

This article is about plant biology. For the Nu metal band, see Taproot (band). For the new age album by Michael Hedges, see Taproot (album).

A plant's taproot is a straight tapering root that grows vertically down. It forms a center from which other roots sprout.

Plants with taproots are difficult to transplant.

The 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 change to a wide-spreading fibrous root system with mainly horizontal 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 to become storage organs.

Some plants with taproots:

Typical taproots

Conical root : another word for taproot.
Fusiform root : tapers at the top and at the bottom, e.g. the taproot of a white radish.
Napiform root : is broader than it is long, e.g. the root of a turnip.

External links and references

[2006-01-13, Sciencedaily: Deep-rooted Plants Have Much Greater Impact On Climate Than Experts Thought] Citat: "...The tap roots transfer rainwater from the surface to reservoirs deep underground and redistribute water...increases photosynthesis and the evaporation of water...by 40 percent in the dry season...During the wet season, these plants can store as much as 10 percent of the annual precipitation as deep as 13 meters (43 feet) underground, to be tapped during the dry months...tree roots acting like pipes to allow water to shift around much faster than it could otherwise percolate through the soil..."
[One reference at Ohio State]
[Fullerton Arboretum on taproots]

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