
On cotton, cucumbers, beans, and grain sorghum, labeled 2,4-D gave rise 
to cl'g, (681, 1478, 1481). Pea and tomato plants have also been studied 
(422). In young leaves and bolls of cotton, material chromatographically 
different from 2,4,-D was formed. Sorghum converted 2,4-D to a complex 
different than that found in cotton (1038, 1081, 1322, 1476, 1477, 1478, 
1479, 1480, 1481). 
Amino acids have been implicated in the formation of some compounds, 
as in the case of 2,4-dichlorophenoxyacetylaspartic acid (27, 62). Evidence 
inditated that 2,4-D moved through plants as a protein complex, which could 
be recovered after aqueous extraction and NaOH hydrolysis, into the roots 
where most of the degradation occurred (225). Resistant plants were grown 
in water cultures treated with 2,4-D. Leaves were homogenized and a 
protein fraction was obtained that contained 2,4-D in a bound form not 
further identified (273). In big leaf maple (Acer Macrophyllum Pursh), 
2,4-D was converted into two metabolites. One of these was the same 
compound characterized previously (214) as a 2,4-D protein complex which 
yielded 2,4-D and 12 amino acids on acid hydrolysis (1087). 
Glucose esters were suggested (314, 798, 799) and studies have shown 
that glucoside complexes were formed. From stem tissues of oats (Avena 
sativa), 1-0-(2,4-dichlorophenoxyacetyl)-B-D-glucose was isolated (1401), 
and from stems of the kidney bean (Phaseolus vulgaris), the 2,5- and 2,3- 
dichlorophenoxyacetic acid glucosides have been obtained (1400). 
From comparative studies with sensitive and insensitive plants, two 
metabolic paths were proposed involving initial glucose ester formation 
and oxidative ring cleavage of the aromatic ring to yield monochloroacetic 
acid (1436). The latter has been detected in plants prior to the onset of 
treatment symptoms; and it has been suggested that the effect of 2,4-D 
resulted from the action of monochloroacetate arising from 2,4-D degradation 
(1436, 1609). 
Plants are capable of hydroxylating phenoxyacetic acids (1399, 1498). 
When bean plants were treated with 2,4-D, three compounds were found (314). 
One corresponded roughly to that of 2,4-dichloranisole; one was water- 
soluble, ether-insoluble ester derivative; and the third, an ether-soluble 
compound with a basic structural change. The methyl derivative was less 
volatile than 2,4-D methyl ester, but more volatile than the 5-hydroxy- 
2,4~D methyl ester. It might be one of the other two hydroxy derivatives; 
however, 6-hydroxy-2,4-D was not detected (60, 420, 680, 726, 727). 
The biotransformation of 2,4-dichlorophenoxyalkanoic acids and related 
compounds by soil microflora has been extensively studied (44, 45, 46, 48 
51, 101, 216, 217, 218, 284, 419, 420, 438, 442, 644, 734, 1083, 1349, 1467, 
5 1468, 1469). Phenoxyalkanoic acids with an even number of carbons in the 
111 
