Basis for Differential Chemical Selectivity of MG-191 Safener against Acetochlor and EPTC Injury to Maize

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Abstract

The influence of MG-191 safener on the uptake, translocation and metabolism of [14C]acetochlor and [,4C]EPTC was studied. The amounts of absorbed radioactivity by maize seedlings at 3, 6, 24, and 72 h after applications of [14C]labeled herbicides and [I4C]MG-191 were different. Plants treated with [l4C]acetochlor took up 30- to 50-fold more radiolabel within 72 h than [14C]EPTC- or [14C]MG-191-treated plants. Addition of MG-191 caused only minor changes in the rate of herbicide absorption. EPTC and MG-191 and/or their metabolites moved quickly acropetally and partitioned equally between root and shoot tissues up to 72 h. The amount of acetochlor and/or its labeled metabolites translocated to shoot tissues was less than 10%. MG-191 practically had no influence on herbicide translocation rates. With all chemicals the amounts of water-soluble and unextractable fractions increased while the ratio of hexane-extractable metabolites decreased with time. TLC analyses of both water- and hexane-soluble metabolites confirmed the fast metabolism of acetochlor. The acetochlor metabolism took place via GSH conjugation and more polar, non-conjugated metabolites compared to parent molecule were detected in hexane-soluble fraction. MG-191 enhanced acetochlor metabolism by decreasing the portion of non-metabolized acetochlor. EPTC metabolism resulted in water-soluble metabolites having similar chromatographic properties to those of acetochlor. However, there was no safener effect on non-metabolized EPTC content of plants. It appears that MG-191 protects maize against EPTC by enhancing the early rate of conjugation with GSH after initial oxidative metabolism.

Original languageEnglish
Pages (from-to)836-845
Number of pages10
JournalZeitschrift fur Naturforschung - Section C Journal of Biosciences
Volume46
Issue number9-10
DOIs
Publication statusPublished - Oct 1 1991

Fingerprint

Zea mays
Metabolites
Metabolism
Wounds and Injuries
Herbicides
Hexanes
Water
Tissue
EPTC
acetochlor
Radioactivity
Seedlings
Molecules

Keywords

  • Acetochlor
  • Chemical Selectivity
  • EPTC
  • Metabolism
  • MG-191
  • Safener
  • Translocation
  • Uptake

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

@article{7f8fdb7cfd0c4a77a9edfa6a182185e3,
title = "Basis for Differential Chemical Selectivity of MG-191 Safener against Acetochlor and EPTC Injury to Maize",
abstract = "The influence of MG-191 safener on the uptake, translocation and metabolism of [14C]acetochlor and [,4C]EPTC was studied. The amounts of absorbed radioactivity by maize seedlings at 3, 6, 24, and 72 h after applications of [14C]labeled herbicides and [I4C]MG-191 were different. Plants treated with [l4C]acetochlor took up 30- to 50-fold more radiolabel within 72 h than [14C]EPTC- or [14C]MG-191-treated plants. Addition of MG-191 caused only minor changes in the rate of herbicide absorption. EPTC and MG-191 and/or their metabolites moved quickly acropetally and partitioned equally between root and shoot tissues up to 72 h. The amount of acetochlor and/or its labeled metabolites translocated to shoot tissues was less than 10{\%}. MG-191 practically had no influence on herbicide translocation rates. With all chemicals the amounts of water-soluble and unextractable fractions increased while the ratio of hexane-extractable metabolites decreased with time. TLC analyses of both water- and hexane-soluble metabolites confirmed the fast metabolism of acetochlor. The acetochlor metabolism took place via GSH conjugation and more polar, non-conjugated metabolites compared to parent molecule were detected in hexane-soluble fraction. MG-191 enhanced acetochlor metabolism by decreasing the portion of non-metabolized acetochlor. EPTC metabolism resulted in water-soluble metabolites having similar chromatographic properties to those of acetochlor. However, there was no safener effect on non-metabolized EPTC content of plants. It appears that MG-191 protects maize against EPTC by enhancing the early rate of conjugation with GSH after initial oxidative metabolism.",
keywords = "Acetochlor, Chemical Selectivity, EPTC, Metabolism, MG-191, Safener, Translocation, Uptake",
author = "I. Jablonkai",
year = "1991",
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T1 - Basis for Differential Chemical Selectivity of MG-191 Safener against Acetochlor and EPTC Injury to Maize

AU - Jablonkai, I.

PY - 1991/10/1

Y1 - 1991/10/1

N2 - The influence of MG-191 safener on the uptake, translocation and metabolism of [14C]acetochlor and [,4C]EPTC was studied. The amounts of absorbed radioactivity by maize seedlings at 3, 6, 24, and 72 h after applications of [14C]labeled herbicides and [I4C]MG-191 were different. Plants treated with [l4C]acetochlor took up 30- to 50-fold more radiolabel within 72 h than [14C]EPTC- or [14C]MG-191-treated plants. Addition of MG-191 caused only minor changes in the rate of herbicide absorption. EPTC and MG-191 and/or their metabolites moved quickly acropetally and partitioned equally between root and shoot tissues up to 72 h. The amount of acetochlor and/or its labeled metabolites translocated to shoot tissues was less than 10%. MG-191 practically had no influence on herbicide translocation rates. With all chemicals the amounts of water-soluble and unextractable fractions increased while the ratio of hexane-extractable metabolites decreased with time. TLC analyses of both water- and hexane-soluble metabolites confirmed the fast metabolism of acetochlor. The acetochlor metabolism took place via GSH conjugation and more polar, non-conjugated metabolites compared to parent molecule were detected in hexane-soluble fraction. MG-191 enhanced acetochlor metabolism by decreasing the portion of non-metabolized acetochlor. EPTC metabolism resulted in water-soluble metabolites having similar chromatographic properties to those of acetochlor. However, there was no safener effect on non-metabolized EPTC content of plants. It appears that MG-191 protects maize against EPTC by enhancing the early rate of conjugation with GSH after initial oxidative metabolism.

AB - The influence of MG-191 safener on the uptake, translocation and metabolism of [14C]acetochlor and [,4C]EPTC was studied. The amounts of absorbed radioactivity by maize seedlings at 3, 6, 24, and 72 h after applications of [14C]labeled herbicides and [I4C]MG-191 were different. Plants treated with [l4C]acetochlor took up 30- to 50-fold more radiolabel within 72 h than [14C]EPTC- or [14C]MG-191-treated plants. Addition of MG-191 caused only minor changes in the rate of herbicide absorption. EPTC and MG-191 and/or their metabolites moved quickly acropetally and partitioned equally between root and shoot tissues up to 72 h. The amount of acetochlor and/or its labeled metabolites translocated to shoot tissues was less than 10%. MG-191 practically had no influence on herbicide translocation rates. With all chemicals the amounts of water-soluble and unextractable fractions increased while the ratio of hexane-extractable metabolites decreased with time. TLC analyses of both water- and hexane-soluble metabolites confirmed the fast metabolism of acetochlor. The acetochlor metabolism took place via GSH conjugation and more polar, non-conjugated metabolites compared to parent molecule were detected in hexane-soluble fraction. MG-191 enhanced acetochlor metabolism by decreasing the portion of non-metabolized acetochlor. EPTC metabolism resulted in water-soluble metabolites having similar chromatographic properties to those of acetochlor. However, there was no safener effect on non-metabolized EPTC content of plants. It appears that MG-191 protects maize against EPTC by enhancing the early rate of conjugation with GSH after initial oxidative metabolism.

KW - Acetochlor

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KW - Metabolism

KW - MG-191

KW - Safener

KW - Translocation

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DO - 10.1515/znc-1991-9-1019

M3 - Article

VL - 46

SP - 836

EP - 845

JO - Zeitschrift fur Naturforschung. Section C: Biosciences

JF - Zeitschrift fur Naturforschung. Section C: Biosciences

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