Study On Uptake And Accumulation Of Acephate And Carbendazim In Plants

Selecting organic pollutants acephate (ACE) and carbendazim (MBC) as the researchobjects, uptake, accumulation in aqueous solution-plant system and their influence factorsunder the conditions of hydroponics were studied. The main results of the research aresummarized as follows:(1) UPLC/MS/MS methods were established for the determination of ACE and itsmetabolite MAP, MBC and its metabolites (2-aminobenzimidazole (2-AB) andbenzimidazole (BEN)) residues in tomatoes. The LOD and LOQ of ACE were2.11μg/kgand3.52μg/kg, respectively, while the LOD and LOQ of MAP were1.64μg/kg and1.69μg/kg, respectively. The recoveries of ACE ranged from98.7%to105.7%, while theRSD was3.5%to9.2%, and the recoveries of MAP ranged from86.4%to98.8%, whilethe RSD was2.2%to12.3%for all samples spiked with0.02to2.0mg/kg of ACE andMAP. The LOD and LOQ of MBC were4.73μg/kg and4.99μg/kg, and the LOD andLOQ of BEN were0.98μg/kg and2.60μg/kg, while the LOD and LOQ of2-AB were0.16μg/kg and0.29μg/kg. The recoveries of MBC ranged from94.5%to104.9%, whilethe RSD was2.9%to5.9%, the recoveries of BEN ranged from70.5%to88.9%, while theRSD was4.6%to6.8%, and the recoveries of2-AB ranged from78.8%to84.7%, whilethe RSD was2.6%to9.5%for all samples spiked with0.05to5.0mg/kg of MBC,2-ABand BEN. The results showed that the methods accorded with demands of the residueanalysis in tomatoes.(2)We confirmed that ACE and MBC could be absorbed by roots and uptake totomato seedlings. Treat plants with concentration of1.0mg/L, it cost about12h to achievedynamic equilibrium state for the absorption of ACE from nutrient solution to tomatoseedlings, while it cost about48h for the absorption of MBC. We also found that theamounts of ACE and MBC in xylem exudate were quite different, when treat with differentconcentration of0.1、0.5、1.0、5.0、10.0mg/L for48h. The ACE concentration in xylemexudate increased with the raising of the ACE concentration in nutrient solution. The MAPconcentration in xylem exudate increased with the raising of the ACE concentration (1、5、10mg/L) in nutrient solution. The MBC concentration in xylem exudate increased with theraising of the MBC concentration in nutrient solution. The2-AB and BEN concentration inxylem exudate increased with the raising of the MBC concentration (5、10mg/L) in nutrient solution. The concentration of ACE in xylem exudate had no significant difference amongtreatment with1.0mg/L ACE (pH4, pH6, pH8) for48h, while MBC uptook most at pH4.Light intensity effected the concentration of ACE and MBC in xylem exudate.(3) ACE and MBC uptake in phloem of castor bean had been studied, dealing withdifferent concentrations (0.1、0.5、1.0、5.0、10.0mg/L) for48h. The results showed thatthe amounts of ACE and MBC in xylem exudate and phloem exudate were quite different.The concentration of ACE and MBC in xylem exudate and phloem exudate increased withthe raising of ACE and MBC in nutrient solution, respectively.(4) ACE and MAP could be found respectively from the ripe tomatoes constantlyexposed to0.1、1.0and10mg/L ACE for different time, and the concentration of ACE washigher than MAP for each treatment. MBC and2-AB could be found from the ripetomatoes constantly exposed to1.0and10mg/L MBC, and the concentration of MBC waslower than2-AB for each treatment.