5. Conclusions
This
study showed that exogenous SA (10mg L-1) could
promote the degradation of three pesticides in nutrient solution and
suppress the accumulation of three pesticides in roots and leaves.
Noteworthy, the role of SA in reducing pesticide residues was related to
the accumulation sites of cucumber plants. Through the calculation of
root concentration factor (RCF) and translocation factor (TF), it was
found that exogenous SA (10mg L-1) significantly
weakened the absorption capacity of roots to the three pesticides.
Whereas, the translocation capacity of the three pesticides in cucumber
plants were enhanced with three concentrations of SA supplementation.
According to our study, single root exposure of three pesticides all
caused phytotoxicity, which showed that the plants biomass decreased,
chlorophyll synthesis was inhibited, proline accumulation increased,
lipid peroxidation was promoted, and the activities of antioxidant
enzyme (SOD, APX and GST) was destroyed, respectively. However, these
adverse effects could be alleviated by supplementing with appropriate
concentration of exogenous SA (1mg L-1 and 10mg
L-1). This
present study provided evidence that SA could reduce the accumulation of
pesticides in plants and provided a basis for the application of
exogenous SA in agricultural production. However, the exact interaction
mechanism between pesticides and SA in plants needs to be further
elucidated.
Acknowledgement
This work was supported by
National Natural Science Foundation of China (31801781), Guangxi Special
Fund Project (AA17204043-1), Natural Science Foundation of Shandong
Province (ZR2018BC038), and National Key R&D Program of China
(2016YFD0200206).