title: Enantioselective uptake and translocation of a novel chiral neonicotinoid insecticide cycloxaprid in Youdonger (Brassica campestris subsp. Chinensis).
abstract: For a novel potential commercial chiral pesticide, an independent study on the fate characteristics and residues of each stereoisomer is essential if the application rates for the pesticide and human exposure are to be reduced. The absorption and translocation behavior of a chiral insecticide, cycloxaprid, in plants treated by root immersion and blade smearing was studied using (14)C-labeling tracer techniques. With the root treatment, total absorption of (1R;8S)-cycloxaprid (RS) (12.39%) was much greater than that of (1S;8R)-cycloxaprid (SR) (3.31%) at 192 h after treatment (HAT). The mass concentrations (RS/SR) of cycloxaprid in the roots, cotyledons, leaf 1, leaf 2, and leaf 3 were 37.0/16.8, 8.3/2.8, 11.7/6.5, 5.1/4.8, and 8.0/4.7 mg kg(-1) (fresh weight), respectively, at 192 HAT at an initial concentration 1.6 mg kg(-1). With the foliar application treatment, no significant difference was observed between the total absorption of RS (3.11%) and SR (4.03%) at the end of the treatment. Both acropetal and basipetal transport of absorbed (14)C occurred and more than 71.83% of absorbed RS and 82.42% of SR remained in the treated leaf. Stereoselective absorption was observed during root uptake but not during foliar absorption.
authors.affiliation: Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Zhang
authors.forename: Qiuguo
authors.initials: Q
authors.lastname: Fu
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Juying
authors.initials: J
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.forename: Sufen
authors.initials: S
authors.lastname: Zhang
authors.forename: Qingfu
authors.initials: Q
authors.lastname: Ye
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li
mesh_terms: D000042:Absorption; D001692:Biological Transport; D001937:Brassica / Q000378:metabolism*; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry* / Q000378:metabolism*; D007306:Insecticides / Q000737:chemistry* / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D011725:Pyridines / Q000737:chemistry* / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D006575:Heterocyclic Compounds, 3-Ring; D007306:Insecticides; D011725:Pyridines; C583366:cycloxaprid
keywords: cycloxaprid; foliar absorption; neonicotinoid; pesticide; root uptake; stereoselective