Atrazine metabolism and herbicidal selectivity

Shimabukuro, R.H. (1967) Atrazine metabolism and herbicidal selectivity. Plant Physiology, 42 (9). pp. 1269-1276.

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Abstract

Metabolism of the herbicide 2-chloro-4-ethylamino-6-isopropylamino-s-triazine(atrazine) was investigated in resistant corn (Zea mays L.) and sorghum (Sorghum zlvlgare Pers.), intermediately susceptible pea (Pisuim sativum L.), and highly susceptible heat (Triticum vulgare Vill.) and soybean (Glycine max Merril.). This study revealed that 2 possible pathways for atrazine metabolism exist in higher plants. All species studied were able to metabolize atrazine initially by N-dealkylation of either of the 2 substituted alkylamine groups. Corn and wheat, which contain benzoxazinone, also metabolized atrazine initially by hydrolysis in the 2-position of the s-triazine ring to form hydroxyatrazine. Subsequent metabolism by both pathways resulted in th-e conversion of the parent atraztine to more polar conmpounds and eventually into methanol-insoluble plant residue.No evidence for s-triazine ring cleavage was obtained.Both pathways for atrazine metabolism appear to detoxify atrazine. The hydroxylation pathway results in a direct conversion of a highly phytotoxic compound to a completely non-phytotoxic derivative. The dealkylation pathway leads to detoxication through one or more partially detoxified, stable intermediates. Therefore, the rate and pathways of atrazine metabolism are important in determining the tolerance of plants to the herbicide.Both quantitative and qualitative dififerences in atrazine metabolism were detected between resistant, intermediately susceptible, and susceptible species. The ability of plants to metabolize atrazine by N-dealkylation andl the influence of thhis pathway in determining tolerance of plants to atrazine are discussed.

Item Type:	Article
Author Affiliation:	Metabolism and Radiation Research Laboratory, Crops Research Division, ARS, USDA, Fargo, North Dakota 58102
Subjects:	Plant Physiology and Biochemistry > Plant Physiology
Divisions:	Maize Sorghum Soyabean
Depositing User:	Sandhya Gir
Date Deposited:	09 Nov 2010 17:51
Last Modified:	29 Dec 2010 20:40
Official URL:	http://www.plantphysiol.org/cgi/reprint/42/9/1269....
URI:	http://eprints.icrisat.ac.in/id/eprint/535

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