title: Enantioselective effects of herbicide imazapyr on Arabidopsis thaliana.
abstract: The enantioselective toxicity of chiral herbicides in the environment is of increasing concern. To investigate the enantioselective effects of the chiral herbicide imazapyr on target organisms, we exposed Arabidopsis thaliana to imazapyr enantiomers and racemate. The results show that imazapyr was enantioselectively toxic to A. thaliana. The total chlorophyll content in A. thaliana was affected more by (+)-imazapyr than (±)-imazapyr and (-)-imazapyr. Concentrations of proline and malondialdehyde reflected a toxic effect in the order of (+)-imazapyr > (±)-imazapyr > (-)-imazapyr at every concentration. Acetolactate synthase (ALS) activity was inhibited more by (+)-imazapyr than (±)-imazapyr or (-)-imazapyr. At 100 mg L(-1) of imazapyr, ALS activity was 78%, 43%, and 19% with (-)-, (±)-, and (+)-imazapyr, respectively. The results suggest the significant enantioselective toxicity of imazapyr in A. thaliana for greater toxicity with (+)-imazapyr than (±)-imazapyr and (-)-imazapyr, which suggests that (+)-imazapyr has more herbicidal effect.
authors.affiliation: a Department of Agricultural Chemistry , National Taiwan University , Taipei , Taiwan.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Hsiao
authors.forename: Yei-Shung
authors.initials: YS
authors.lastname: Wang
authors.forename: Jui-Hung
authors.initials: JH
authors.lastname: Yen
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology*; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D009525:Niacin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D006540:Herbicides; D007093:Imidazoles; D009525:Niacin; C076656:imazapyr
keywords: Arabidopsis thaliana; Imidazolinones; acetolactate synthase (ALS); enantioselectivity; imazapyr