Comparative Uptake, Translocation and Metabolism of Phenamacril in Crops under Hydroponic and Soil Cultivation Conditions

Many studies investigate the plant uptake and metabolism of xenobiotics by hydroponic experiments, however, plants grown in different conditions (hydroponic vs . soil) may result in different behaviors. To explore the potential differences, a comparative study on the uptake, translocation and metabolism of the fungicide phenamacril in crops (wheat/rice) under hydroponic and soil cultivation conditions was conducted. During 7-14 days of exposure, the translocation factors (TFs) of phenamacril were greatly overestimated in hydroponic-wheat (3.6-5.2) than those in soil-wheat systems (1.1-2.0), with up to 3.3 times of difference between the two cultivation systems, implying it should be cautious to extrapolate the results obtained from hydroponic to field conditions. M-144 was formed in soil pore water (19.1-29.9 mu g/L) in soil-wheat systems but not in the hydroponic solution in hydroponics; M-232 was only formed in wheat shoots (89.7-103.0 mu g/kg) under soil cultivation conditions, however, it was detected in hydroponic solution (20.1-21.2 mu g/L), wheat roots (146.8-166.0 mu g/kg), and shoots (239.2-348.1 mu g/kg) under hydroponic conditions. The root concentration factors (RCFs) and TFs of phenamacril in rice were up to 2.4 and 3.6 times higher than that in wheat for 28 days of the hydroponic exposure, respectively. These results highlighted that cultivation conditions and plant species could influence the fate of pesticides in crops, which should be considered to better assess the potential accumulation and trans- formation of pesticides in crops.