Nontarget mechanims involved in glyphosate tolerance found in Canavalia ensiformis plants.
A glyphosate-tolerant population of Canavalia ensiformis was collected in a cover crop in citrus orchards in Veracruz (Mexico), where glyphosate had been used for the first time. A susceptible Amaranthus hybridus L. population was collected from a nearby field that had never been treated with glyphosate. Dose-response experiments indicated a glyphosate tolerance ratio [ED(50)(C. ensiformis)/ED(50) (A. hybridus)] of 7.7. The hypothesis of a high level of glyphosate tolerance was provisionally corroborated on the basis of shikimate accumulation in both species. The susceptible population accumulated 6 times more shikimic acid in leaf tissue 96 h after glyphosate application than the tolerant leguminous crop. Two different physiological factors were involved in the glyphosate tolerance of this C. ensiformis population, which were confirmed by [(14)C]glyphosate, being a lack of penetration of glyphosate through the cuticle of the leguminous plants and an impaired herbicide translocation to the roots and the rest of shoots. This paper reports that two different nontarget site-based mechanisms, limited absorption and reduced translocation, contribute to the glyphosate tolerance found in C. ensiformis.
Department of Agricultural Chemistry and Edaphology, University of Cordoba, Cordoba, Spain. g32crhih@uco.es
Hugo
H
Cruz-Hipolito
Maria D
MD
Osuna
Antonio
A
Heredia
Juan Pedro
JP
Ruiz-Santaella
Rafael
R
De Prado
D027721:Amaranthus / Q000187:drug effects* / Q000502:physiology; D032449:Canavalia / Q000187:drug effects* / Q000502:physiology; D004351:Drug Resistance; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D012765:Shikimic Acid / Q000378:metabolism; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D012765:Shikimic Acid; D000097797:Glyphosate