Exogenous salicylic acid alleviates the accumulation of pesticides and
mitigates pesticide-induced oxidative stress in cucumber plants
Abstract
Salicylic acid (SA) is an important signal molecule, regulating
oxidative stress response in plants. In this study, we evaluated the
influences of SA (1mg L-1, 10mg L-1 and 50mg L-1) on the accumulation of
clothianidin (CLO), dinotefuran (DFN) and difenoconazole (DFZ) (5mg L-1)
and pesticide-induced (CLO-10mg L-1, DFN-20 mg L-1, and DFZ-10mg L-1)
oxidative stress in cucumber plants. Exogenous SA at 10mg L-1
significantly reduced the half-lives of three pesticides in nutrient
solution and prevented the accumulation of pesticides in roots and
leaves. And the role of SA in reducing residues was related to the major
accumulation sites of pesticides. By calculating the root concentration
factor (RCF) and translocation factor (TF), we found that SA at 10mg L-1
reduced the ability of roots to absorb pesticides and enhanced the
translocation ability from roots to leaves. Roots exposed to high
concentrations of three pesticides could reduce biomass, low chlorophyll
content, promote lipid peroxidation, and alter the activities of a range
of antioxidant enzymes, respectively. Exogenous SA at low concentrations
significantly mitigated these negative effects. Hence, we speculated
that application of exogenous SA at 10 mg L-1 could effectively
alleviate the accumulation of pesticides and induce stress tolerance in
cucumber planting systems.