title: Stereoselective uptake and distribution of the chiral neonicotinoid insecticide, Paichongding, in Chinese pak choi (Brassica campestris ssp. chinenesis).
abstract: Neonicotinoid chiral insecticidal Paichongding is a promising substitute for the widely used imidacloprid. Four stereoisomers of Paichongding, 5R,7R, 5S,7S, 5S,7R and 5R,7S, were employed in both foliage and roots of Chinese pak choi to investigate their stereoselective uptake and distribution in pak choi. Results showed that after foliar application, no stereoselective absorption into pak-choi plants was observed among the enantiomers. Total absorptions were 35.40% of the applied amount for 5R,7R, 36.66% for 5S,7S, 36.80% for 5S,7R and 38.20% for 5R,7S at 96 HAT. The translocation of the four absorbed stereoisomers within pak choi occurred both acropetally and basipetally and the transport of (14)C from enantiomers 5R,7R and 5S,7S were significantly higher than for 5R,7S and 5S,7R. Significant stereoselective translocation inside plants was observed between Paichongding epimers. Total root uptake reached 16.49-19.85% for 5R,7R and 5S,7S, and 24.57-28.82% for 5S,7R and 5R,7S at 144 HAT. Both enantioselective and diastereoselective root uptake into pak-choi occurred between the four stereoisomers. The 5R,7S and 5S,7R enantiomers were more readily uptaken by the roots than 5R,7R and 5S,7S and accumulated in the edible leaves. These results will help to develop an understanding of Paichongding using only the target-active enantiomer of pesticides.
authors.affiliation: Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Zhejiang University, Hangzhou 310029, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.forename: Ruyang
authors.initials: R
authors.lastname: Liu
authors.forename: Qiuguo
authors.initials: Q
authors.lastname: Fu
authors.forename: Sufen
authors.initials: S
authors.lastname: Zhang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Cai
authors.forename: Juying
authors.initials: J
authors.lastname: Li
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhao
authors.forename: Qingfu
authors.initials: Q
authors.lastname: Ye
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li
mesh_terms: D000042:Absorption; D053961:Azabicyclo Compounds / Q000032:analysis / Q000493:pharmacokinetics*; D001692:Biological Transport; D001937:Brassica / Q000378:metabolism*; D002250:Carbon Radioisotopes / Q000032:analysis; D005506:Food Contamination / Q000032:analysis*; D007306:Insecticides / Q000032:analysis / Q000493:pharmacokinetics*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D011725:Pyridines / Q000032:analysis / Q000493:pharmacokinetics*; D013237:Stereoisomerism
chemical_list: D053961:Azabicyclo Compounds; D002250:Carbon Radioisotopes; D007306:Insecticides; D011725:Pyridines; C588015:paichongding
keywords: Foliar absorption; Paichongding; Root uptake; Stereoselective; Translocation