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.