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Any of various derivatives of urea.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. (Elements & Compounds) any of a class of organic compounds derived from urea by replacing one or more of its hydrogen atoms by organic groups
2. (Elements & Compounds) any of a class of derivatives of urea and carboxylic acids, in which one or more of the hydrogen atoms have been replaced by acyl groups: includes the cyclic ureides, such as alloxan
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈyʊər iˌaɪd, -ɪd)

an acyl urea.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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[42] Atkins, C.A., and Smith, P.M.C., 2000, "Ureide synthesis in legume nodules.
An additional finely ground biomass subsample was analyzed for total ureide content using the following procedure.
Soybean N2 fixation estimates, ureide concentration, and yield responses to drought.
Sinclair and Serraj (1995) reported that warm-season species that accumulated high concentrations of ureides (>200 mmol [L.sup.-1] xylem sap) were more drought-sensitive than species with <50 mmol [L.sup.-1] xylem sap or no ureide.
Other nonnodulating genotypes have subsequently been isolated and one study showed that, in fact, the nonnodulating mutants contained much lower concentration of ureide in developing pods (Matsumoto et al., 1977).
Inheritance studies using ureide accumulation (Kueneman et al., 1984) and acetylene reduction (Chowdhury and Doto, 1981) screening techniques for promiscuous nodulation also obtained inconclusive results.
[2] RAU = (4 x ureide cone.)/[(4 x ureide conc.) + N[O.sup.-.sub.3;] conc.]
Recent studies have focused on ureide accumulation and feedback on nodule activity as being crucial in influencing soybean [N.sub.2] fixation activity.
The involvement of Mn in the response to water deficit and the regulation of ureide levels in leaves of some soybean cultivars has been documented in experiments in which increased Mn supply increased leaf ureide degradation rates and ameliorated [N.sub.2] fixation sensitivity to water deficit (Purcell et al., 2000; Vadez et al., 2000).
(1999a) proposed that decreased demand for amino acids during water deficit resulted in asparagine accumulation, which has been shown to inhibit leaf ureide breakdown (Lukaszewski et al., 1992).