手性甲霜灵在烟草不同部位叶片中的立体选择性行为

Stereoselective Behavior of Chiral Metalaxyl in Different Parts of Tobacco Leaves

[目的]明确甲霜灵对映体在烟草不同部位叶片中含量及立体选择性变化规律。[方法]利用高效液相色谱串联质谱建立甲霜灵对映体分析方法,以温室盆栽灌根的方式研究烟草不同部位叶片中对映体含量及比例差异。[结果]甲霜灵被烟草根部吸收后迅速转运至叶片中,不同部位叶片中含量均呈现先上升后下降的趋势;上部叶片中无明显的立体选择性行为,中、下部叶片存在显著的立体选择性行为,S-甲霜灵优先于R-甲霜灵(精甲霜灵)降解,且叶片部位越低,立体选择性行为越明显。[结论]烟草中、下部叶片中低效的S-甲霜灵优先于高效的R-甲霜灵降解,综合考虑烟叶生产中应加大精甲霜灵的推广力度。

[Aims] In order to study the content and stereoselectivity of metalaxyl enantiomers in different parts of tobacco leaves. [Methods] The HPLC-MS/MS method for the determination of metalaxyl enantiomers was established,the content and proportion of metalaxyl in different parts of tobacco leaves were studied by means of pot root irrigation in greenhouse. [Results] Metalaxyl was quickly transported from the roots to tobacco leaves, and the contents of metalaxyl in different parts of leaves were first increased and then decreased, there was no obvious stereoselective behavior in upper leaves, but the stereoselective behavior was obvious in middle and lower leaves.（＋）-S-metalaxyl degraded faster than（-）-R-metalaxyl, and in the lower position leaves, the stereoselectivity is more obvious.[Conclusions] In the middle and lower leaves of tobacco, the low efficiency（＋）-S-metalaxyl degraded faster than the high efficiency（-）-R-metalaxyl, and the promotion of（-）-R-metalaxyl should be strengthened in tobacco production.