# Physiological and Biochemical Variations in Celery by Imidacloprid and Fenpyroximate
## 3 Results  
### Imidacplorid and Fenpyroximate Residue Concentration  
According to the quantitative data from the LCMS-8050 (Figure 1), the residue concentrations of IMI and FEN were analyzed. As shown in Figure 1A, the initial residue amounts (2 h after application) of pesticides IMI in celery after spraying at the concentration of 1 F fluctuated within range of 0.85 \(\pm\) 0.1 mg kg\({}^{-1}\) (in stem) and 3.31 \(\pm\) 0.28 mg kg\({}^{-1}\) (in leaf), respectively. The initial degradation rates of IMI in stem and leaf were 35.83% and 80.60%, with the degradable loading rates of 0.015 mg kg\({}^{-1}\) d\({}^{-1}\) and 0.133 mg kg\({}^{-1}\) d\({}^{-1}\), respectively. For another pesticide FEN, the initial residues in celery were 1.16 \(\pm\) 0.06 mg kg\({}^{-1}\) (in stem) and 3.68 \(\pm\) 0.14 mg kg\({}^{-1}\) (in leaf), respectively, its initial degradation rates were 26.72% and 74.46% (highest in stems and leaves), with the degradable loading rates of 0.016 mg kg\({}^{-1}\) d\({}^{-1}\) and 0.137 mg kg\({}^{-1}\) d\({}^{-1}\) in stem and leaf. The highest degradation rate of IMI in celery was 91.35% (contrast stem and leaf) with a degradable loading rate of 0.001 mg kg\({}^{-1}\) d\({}^{-1}\) between 5 days and 8 days. Noteworthy, celery (whether stem or leaf) first had a dramatic reduction in 24 h and then exhibited a slow degradation (Figure 1A). For the degradation of pesticides IMI and FEN spraying at a concentration of 1 F, the stem and leaf of celery showed a significant difference, pesticides IMI and FEN residues in leaves were much higher than those in stems, which might be attributed to the fact that leaves in celery are more exposed to pesticides when spraying pesticides. In terms of pesticides, IMI and FEN spraying at a concentration of 10 F (Figure 1B), the initial IMI concentration was 5.76 \(\pm\) 0.22 mg kg\({}^{-1}\) (in stem) and 30.86 \(\pm\) 0.60 mg kg\({}^{-1}\) (in leaf). The initial degradation rates of IMI in stem and leaf were 10.92% and 51.73%. Additionally, its highest degradation rates were 73.22% and 78.41% on 8 days and 14 days, with degradable loading rates of 0.005 mg kg\({}^{-1}\) d\({}^{-1}\) and 0.009 mg kg\({}^{-1}\) d\({}^{-1}\), respectively. For FEN, its initial concentrations were 6.97 \(\pm\) 0.21 mg kg\({}^{-1}\) (in stem) and 21.47 \(\pm\) 0.22 mg kg\({}^{-1}\) (in leaf). Additionally, its highest degradation rates were 87.69 % (in stem) and 76.97 % (in leaf) on 21 days, with degradable loading rates of 0.003 mg kg\({}^{-1}\) d\({}^{-1}\) and 0.007 mg kg\({}^{-1}\) d\({}^{-1}\), respectively. The results in Figure 1B showed that celery (whether stem or leaf) first underwent a rapid absorption process, followed by a rapid degradation of the pesticides in 3 days, and then emerged a slight degradation pattern. The residue amounts of IMI at 10 F (0.01 mg kg\({}^{-1}\) in stem and 0.005 mg kg\({}^{-1}\) in leaf) were far below the maximum residuelimits (MRL: 5 mg kg\({}^{-1}\)) [20]. The residues of FEN in stem and leaf were 0.41 mg kg\({}^{-1}\) and 0.33 mg kg\({}^{-1}\), which were far below initial FEN concentrations (the MRL of FEN has not been specified). In the present study, the residual concentration levels of the two pesticides in celery all followed the sequence: leaf > stem. Ultimately, there was no significant difference in pesticide IMI and FEN residues in stems and leaves after 28 days of application at a concentration of 10 F.  
The results obtained from the residue trial (stem and leaf) showed that pesticides IMI and FEN sprayed at the concentrations of 1 F and 10 F in celery degraded, complying with first-order kinetics (Table 1). The R values of residual kinetic equations ranged from 0.815 to 0.991, yet having a good fit with first-order kinetics under the condition of complexity and uncertainties in the experimental field. The above results are consistent with plenty of published papers [21; 22].