{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/76436"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/76436","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Physiological studies with the experimental herbicide isouron","abstract":"Laboratory studies were conducted to investigate the mode of action of a new herbicide, isouron (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N,N-dimethylurea). These studies included two plant metabolites of isouron, a monomethylurea (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N-methylurea) and a urea derivative (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-urea). The compounds were examined for their effects on four metabolic processes of enzymatically isolated soybean (Glycine max L.) leaf cells. The processes examined were photosynthesis, protein, ribonucleic acid (RNA) and lipid synthesis. Relative incorporation of radiolabeled precursors was the parameter measured to assess herbicidal effects. Results indicate that isouron and its monomethylurea derivative possess similar herbicidal properties. The urea derivative revealed substantially reduced herbicidal effectiveness. The primary mode of action of these compounds appears to be inhibition of photosynthesis. Experiments to determine an I₅₀ value for isouron and experiments to evaluate the influence of an antioxidant EDU (N-(2-(2-oxo-1-imidazolidinyl)ethyl)-N’-phenylurea) and a singlet oxygen quencher DABCO (1,4-diazobicyclo-(2,2,2)-octane) on the photosynthetic inhibition and chlorophyll breakdown induced by isouron were also conducted. An I₅₀ value of 0.51 uM was calculated for isouron. There was no significant influence of EDU or DABCO on isouron toxicity. Greenhouse experiments were conducted to assess the interactions of isouron and four herbicide antidotes on two varieties of corn (Zea mays L.), Dekalb 'XL72AA' and 'XL67', and wheat (Triticum aestivum L.), 'Tyler' and 'McNair 1003'. Antidotes used were naphthalic anhydride (1,8 naphthalic anhydride), R-25788 (N,N-diallyl-2,2-dichloroacetamide), CGA-43089 (α-((cyanomethoxy)imino)benzene acetonitrile) and CGA-92194 (α-((1,3-dioxolan-2-yl-methoxy)imino)benzene acetonitrile. Statistically significant antagonistic interactions between herbicide and antidote were observed in both wheat and corn. Synergistic interactions were also recorded. The order of antidotal effectiveness on corn was determined to be: NA > CGA-43089 > CGA-92194 > R-25788 and in wheat: NA > CGA-43089 > R-25788 (CGA-92194 severely limited germination). Visual observation of both corn and wheat plants indicated that nonantidoted isouron was very toxic to these crops.","abstract_html":"Laboratory studies were conducted to investigate the mode of action of a new herbicide, isouron (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N,N-dimethylurea). These studies included two plant metabolites of isouron, a monomethylurea (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N-methylurea) and a urea derivative (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-urea). The compounds were examined for their effects on four metabolic processes of enzymatically isolated soybean (Glycine max L.) leaf cells. The processes examined were photosynthesis, protein, ribonucleic acid (RNA) and lipid synthesis. Relative incorporation of radiolabeled precursors was the parameter measured to assess herbicidal effects. Results indicate that isouron and its monomethylurea derivative possess similar herbicidal properties. The urea derivative revealed substantially reduced herbicidal effectiveness. The primary mode of action of these compounds appears to be inhibition of photosynthesis. Experiments to determine an I₅₀ value for isouron and experiments to evaluate the influence of an antioxidant EDU (N-(2-(2-oxo-1-imidazolidinyl)ethyl)-N’-phenylurea) and a singlet oxygen quencher DABCO (1,4-diazobicyclo-(2,2,2)-octane) on the photosynthetic inhibition and chlorophyll breakdown induced by isouron were also conducted. An I₅₀ value of 0.51 uM was calculated for isouron. There was no significant influence of EDU or DABCO on isouron toxicity. Greenhouse experiments were conducted to assess the interactions of isouron and four herbicide antidotes on two varieties of corn (Zea mays L.), Dekalb 'XL72AA' and 'XL67', and wheat (Triticum aestivum L.), 'Tyler' and 'McNair 1003'. Antidotes used were naphthalic anhydride (1,8 naphthalic anhydride), R-25788 (N,N-diallyl-2,2-dichloroacetamide), CGA-43089 (α-((cyanomethoxy)imino)benzene acetonitrile) and CGA-92194 (α-((1,3-dioxolan-2-yl-methoxy)imino)benzene acetonitrile. Statistically significant antagonistic interactions between herbicide and antidote were observed in both wheat and corn. Synergistic interactions were also recorded. The order of antidotal effectiveness on corn was determined to be: NA > CGA-43089 > CGA-92194 > R-25788 and in wheat: NA > CGA-43089 > R-25788 (CGA-92194 severely limited germination). Visual observation of both corn and wheat plants indicated that nonantidoted isouron was very toxic to these crops.","abstract_has_math":false,"creators":["Henry, William T."],"institution":"Virginia Polytechnic Institute and State University","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Plant Physiology","degree_department":"Plant Physiology","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1984,"date_issued":"1984","date_published":"1984","updated_at":"2026-07-22T22:20:35Z","subjects":[],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/76436","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Plant Physiology"]},{"key":"dc:creator","label":"Author","values":["Henry, William T."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2017-03-10T21:43:59Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2017-03-10T21:43:59Z"]},{"key":"dc:date.issued","label":"Date","values":["1984"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Plant Physiology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/76436"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Laboratory studies were conducted to investigate the mode of action of a new herbicide, isouron (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N,N-dimethylurea). These studies included two plant metabolites of isouron, a monomethylurea (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N-methylurea) and a urea derivative (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-urea). The compounds were examined for their effects on four metabolic processes of enzymatically isolated soybean (Glycine max L.) leaf cells. The processes examined were photosynthesis, protein, ribonucleic acid (RNA) and lipid synthesis. Relative incorporation of radiolabeled precursors was the parameter measured to assess herbicidal effects. Results indicate that isouron and its monomethylurea derivative possess similar herbicidal properties. The urea derivative revealed substantially reduced herbicidal effectiveness. The primary mode of action of these compounds appears to be inhibition of photosynthesis. Experiments to determine an I₅₀ value for isouron and experiments to evaluate the influence of an antioxidant EDU (N-(2-(2-oxo-1-imidazolidinyl)ethyl)-N’-phenylurea) and a singlet oxygen quencher DABCO (1,4-diazobicyclo-(2,2,2)-octane) on the photosynthetic inhibition and chlorophyll breakdown induced by isouron were also conducted. An I₅₀ value of 0.51 uM was calculated for isouron. There was no significant influence of EDU or DABCO on isouron toxicity. Greenhouse experiments were conducted to assess the interactions of isouron and four herbicide antidotes on two varieties of corn (Zea mays L.), Dekalb 'XL72AA' and 'XL67', and wheat (Triticum aestivum L.), 'Tyler' and 'McNair 1003'. Antidotes used were naphthalic anhydride (1,8 naphthalic anhydride), R-25788 (N,N-diallyl-2,2-dichloroacetamide), CGA-43089 (α-((cyanomethoxy)imino)benzene acetonitrile) and CGA-92194 (α-((1,3-dioxolan-2-yl-methoxy)imino)benzene acetonitrile. Statistically significant antagonistic interactions between herbicide and antidote were observed in both wheat and corn. Synergistic interactions were also recorded. The order of antidotal effectiveness on corn was determined to be: NA > CGA-43089 > CGA-92194 > R-25788 and in wheat: NA > CGA-43089 > R-25788 (CGA-92194 severely limited germination). Visual observation of both corn and wheat plants indicated that nonantidoted isouron was very toxic to these crops."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Physiological studies with the experimental herbicide isouron"]}]}],"canonical_facts":{"dc:contributor.department":["Plant Physiology"],"dc:creator":["Henry, William T."],"dc:date.accessioned":["2017-03-10T21:43:59Z"],"dc:date.available":["2017-03-10T21:43:59Z"],"dc:date.issued":["1984"],"dc:description.abstract":["Laboratory studies were conducted to investigate the mode of action of a new herbicide, isouron (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N,N-dimethylurea). These studies included two plant metabolites of isouron, a monomethylurea (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-N-methylurea) and a urea derivative (N-(5-(1,1-dimethylethyl)-3-isoxazolyl)-urea). The compounds were examined for their effects on four metabolic processes of enzymatically isolated soybean (Glycine max L.) leaf cells. The processes examined were photosynthesis, protein, ribonucleic acid (RNA) and lipid synthesis. Relative incorporation of radiolabeled precursors was the parameter measured to assess herbicidal effects. Results indicate that isouron and its monomethylurea derivative possess similar herbicidal properties. The urea derivative revealed substantially reduced herbicidal effectiveness. The primary mode of action of these compounds appears to be inhibition of photosynthesis. Experiments to determine an I₅₀ value for isouron and experiments to evaluate the influence of an antioxidant EDU (N-(2-(2-oxo-1-imidazolidinyl)ethyl)-N’-phenylurea) and a singlet oxygen quencher DABCO (1,4-diazobicyclo-(2,2,2)-octane) on the photosynthetic inhibition and chlorophyll breakdown induced by isouron were also conducted. An I₅₀ value of 0.51 uM was calculated for isouron. There was no significant influence of EDU or DABCO on isouron toxicity. Greenhouse experiments were conducted to assess the interactions of isouron and four herbicide antidotes on two varieties of corn (Zea mays L.), Dekalb 'XL72AA' and 'XL67', and wheat (Triticum aestivum L.), 'Tyler' and 'McNair 1003'. Antidotes used were naphthalic anhydride (1,8 naphthalic anhydride), R-25788 (N,N-diallyl-2,2-dichloroacetamide), CGA-43089 (α-((cyanomethoxy)imino)benzene acetonitrile) and CGA-92194 (α-((1,3-dioxolan-2-yl-methoxy)imino)benzene acetonitrile. Statistically significant antagonistic interactions between herbicide and antidote were observed in both wheat and corn. Synergistic interactions were also recorded. The order of antidotal effectiveness on corn was determined to be: NA > CGA-43089 > CGA-92194 > R-25788 and in wheat: NA > CGA-43089 > R-25788 (CGA-92194 severely limited germination). Visual observation of both corn and wheat plants indicated that nonantidoted isouron was very toxic to these crops."],"dc:description.degree":["Master of Science"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/76436"],"dc:language.iso":["en_US"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Physiological studies with the experimental herbicide isouron"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Plant Physiology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:35Z"}