Specialized and Modified Roots

Specialized and Modified Roots - or a few parent trees....

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Specialized and Modified Roots Roots often perform functions other than support and absorption. Some store starch  (beets and turnips) or water (desert plants).  Pneumatophores  are roots that grow into  the air and are filled with a specialized parenchyma called  aerenchyma . The large,  intercellular spaces of aerenchyma are filled with oxygen and other gases. The  pneumatophores seem to assist in aerobic respiration and gas exchange and are  abundant on woody plants like cypress and mangrove, which grow in water-logged soils.  Some roots produce  suckers  from adventitious bud-like growths. Suckers grow into  aerial shoots capable of independent existence, and serve to propagate the plant.  Because they have the same genetic make-up as the parent plant, they are  clones  of  the parent. Aspen groves in the western United States frequently are clones of only one 
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Unformatted text preview: or a few parent trees. Many flowering plants develop as parasites on other plants. They produce adventitious roots called haustoria that penetrate the tissues of the host and connect to the vascular system, thus becoming part of the host pipelines. Parasitic roots lack most of the tissues of ordinary roots. Dodder and mistletoe are two of the more than 3000 flowering plant parasites. Mycorrhizal roots are known from 90 percent of plant species and are a mutualistic association of a fungus with plant root tissue. Most plants require specific mycorrhizal fungi without which they are unable to absorb sufficient quantities of P, Zn, and Mn. The fungus takes the place of root hairs and may penetrate the cortex completely ( endomycorrhizae ) or remain on the surface of the root ( ectomycorrhizae )....
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This note was uploaded on 11/14/2011 for the course BIO 1421 taught by Professor Farr during the Fall '08 term at Texas State.

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