Root Hairs


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Root Hairs

 

(pili radicales), outgrowths of the cells of the surface tissue (epiblem) of the absorption zone of a root.

Root hairs contain the parietal layer of protoplasm, the nucleus, and a large vacuole of the epiblemic cells. Their thin mucous walls, readily penetrated by water, stick to clumps of soil, releasing various substances into the soil that convert poorly soluble compounds into forms that are readily assimilable by the plant. Other of these substances aid the development of microflora. The root hairs also serve to support the growing tip of the root.

Root hairs are short-lived, usually dying off in 15–20 days. Their length varies in different plants from 0.06 to 10 mm. On the other hand, the total length, surface, and number of root hairs in a single plant can reach significant quantities (for example, the overall length in a wheat plant is about 20 km). With increased moisture in the soil and poorer aeration, the formation of root hairs slows, and they fail to form at all in very dry soil. Many aquatic and mycotrophic plants (for example, pines and beech) lack root hairs.

R. P. BARYKINA

References in periodicals archive ?
Undistributed soil samples with roots were initially suspended in water for 24 hours and after wards a large number of roots with root hairs were carefully taken by hand.
Dolan, "Ethylene is a positive regulator of root hair development in Arabidopsis thaliana," The Plant Journal, vol.
This may be a mutant variety referred to as rhd2 (root hair defective) mutant spoken of by [15] in their study of failed nodulation in some mutant variety of Arabidopsis.
Both taproot and fibrous root systems increase their surface areas many times by the production of root hairs. Adventitious roots include roots developing at stem nodes as well as prop roots, which help support the stem.
The process begins, they say, with a pas de deux between the legume root hairs, which release flavonoid compounds into the soil, and hang-about bacteria that, in turn, secrete molecules called Nod factors.
Just behind the zone of cell division is a zone of cell elongation and then a zone where root hairs are present.
dense tangles of root hairs strangling one another.
To explain this principle will mean delving into a little physics and chemistry, but you will then easily see the unbalanced nutrition created in chemical fertilized plants Note: The colloidal humus particles are the convoys that transfer most of the minerals from the soil solution to the root hairs. Each humus particle is negatively charged and will, attract the positive elements, such as potassium (K), sodium, calcium, magnesium, manganese, aluminum, boron, iron, copper and other metals.
smooth; secondary roots simple; shoot-borne roots present; root hairs
The key parts of the root are the primary root, secondary root, root hairs, and root cap.
The Rhizobium form nodules in root hairs and fix gaseous nitrogen ([N.sub.2]) into ammonia (N[H.sub.3]) a form the plant can use.
The hyphae are tiny, much smaller than root hairs, and consequently can penetrate into tiny pores in the soil.