Qu Qian, Ke Mingjing, Ye Yizhi, Zhang Qi, Lu Tao, Zhang Zhenyan, Qian Haifeng
College of Environment, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, People's Republic of China.
Bull Environ Contam Toxicol. 2019 Mar;102(3):439-445. doi: 10.1007/s00128-019-02565-6. Epub 2019 Feb 7.
The unfounded use of chiral pesticides has caused widespread concern. In this study, the enantioselective effects of S- and racemic (Rac)-metolachlor on the oxidative stress of wheat seedlings was determined based on physiological and gene transcription differences. Growth inhibition increased with increasing concentrations of tested metolachlor, and S-metolachlor had a stronger inhibitory effect than did Rac-metolachlor. Root growth was also significantly inhibited, but no enantioselective effects from the tested concentrations of the metolachlor enantiomers were observed. At a concentration of 5 mg L, the maximal fresh weight inhibition reached 63.7% and 53.8% for S-metolachlor and Rac-metolachlor, respectively. In response to the S-metolachlor treatment, the maximum level of superoxide anions and malondialdehyde (MDA) increased to 1.73 and 2.55 times that in response to the control treatment, both of which were greater than those in response to the Rac-metolachlor treatment. The activity of superoxide dismutase (SOD) also increased in response to the S-metolachlor treatment, but the activity of peroxidase (POD) decreased. Real-time polymerase chain reaction (PCR) revealed that, compared with the Rac-metolachlor treatment, the S-metolachlor treatment attenuated the expression of several antioxidant genes. Together, these results demonstrate that S-metolachlor has a greater effect than does Rac-metolachlor on wheat seedlings.
手性农药的不合理使用已引起广泛关注。在本研究中，基于生理和基因转录差异，测定了S-异丙甲草胺和外消旋（Rac）-异丙甲草胺对小麦幼苗氧化应激的对映体选择性效应。随着受试异丙甲草胺浓度的增加，生长抑制作用增强，且S-异丙甲草胺的抑制作用比Rac-异丙甲草胺更强。根系生长也受到显著抑制，但在所测试的异丙甲草胺对映体浓度下未观察到对映体选择性效应。在浓度为5 mg/L时，S-异丙甲草胺和Rac-异丙甲草胺对鲜重的最大抑制率分别达到63.7%和53.8%。响应S-异丙甲草胺处理，超氧阴离子和丙二醛（MDA）的最大水平分别增加到对照处理的1.73倍和2.55倍，两者均高于Rac-异丙甲草胺处理。超氧化物歧化酶（SOD）的活性也因S-异丙甲草胺处理而增加，但过氧化物酶（POD）的活性降低。实时聚合酶链反应（PCR）显示，与Rac-异丙甲草胺处理相比，S-异丙甲草胺处理减弱了几种抗氧化基因的表达。总之，这些结果表明S-异丙甲草胺对小麦幼苗的影响比Rac-异丙甲草胺更大。
