3.3 Root concentration factor and translocation concentration factor
To further explore the difference in the uptake and translocation of three pesticides with SA or without SA in the cucumber plants, the root concentration factor (RCF) and translocation factor (TF) were analyzed. The average RCF values of three pesticides are summarized inTable 3 , and the dynamic RCF values of three pesticides during 28-days of exposure are shown in Table S5 . The RCF value ranged from 0.15 to 3.12 for CLO, from 0.2 to 1.11 for DFN, from 26.10 to 148.30 for DFZ during 28-days of exposure. The average RCF values for CLO, DFN, DFZ were 1.07, 0.64 and 52.19, respectively. Whereas with SA supplementing, the average RCF values for the three pesticides were all decreased. For CLO, the average RCF values were significantly decreased by 49%, 35% and 26% with addition of SA at 1mg L-1, 10 mg L-1 and 50 mg L-1, respectively, compared with the treatment of CLO alone. For DFN, the average RCF values were decreased by 6.25% and 11% with addition of SA at 1 mg L-1 and 10mg L-1, respectively, compared with the treatment of DFN alone. For DFZ, the average RCF value was significantly decreased by 16% with addition of SA at 10mg-1 compared with the treatment of DFZ alone.
The average TF values of three pesticides are summarized inTable 4 , and the dynamic TF values of three pesticides during 28-days of exposure are shown in Table S6 and S7 . The average TFstem and TFleaf of CLO, DFN, DFZ were 0.98, 0.69, 0.02 and 8.81, 8.03, 0.005, respectively. In addition to CLO, no significant differences were found for TFstem between the treatment groups with SA supplementation and the groups without SA supplementation, which again demonstrated that pesticides migrated up via the transpiration stream and eventually accumulated in the leaves, and the stems were just a bridge for pesticides upward conduction and reached equilibrium with transpiration stream (Volpe, Marani, Albertson, & Katul, 2013). For CLO, the TFleaf values were significantly increased by 102%, 130% and 31% after adding SA at 1 mg L-1, 10 mg L-1 and 50 mg L-1, respectively, compared with the treatment of CLO alone. For DFN, the TFleaf values were significantly increased by 77% and 43% after adding SA at 10 mg L-1 and 50 mg L-1, respectively, compared with the treatment of DFN alone. For DFZ, the TFleaf values were significantly increased by 160% and 120% after adding SA at 10 mg L-1 and 50 mg L-1, respectively, compared with the treatment of DFZ alone.