Pathway of PAHs entering Brassica parachinensis and its effects on yield and quality of B. parachinensis

ObjectiveThe purpose of this study was to explore the main path ways of polycyclic aromatic hydrocar-bons(PAHs)entering into Brassica parachinensis and provide reference for improving its yield,quality and production safety.MethodAt harvest stage,experiment was carried out through applying five kinds of PAHs on the B. parachinen-sis in leaf smear and root hydroponic treatments. Then PAHs content,yield and nutritional quality of B. parachinensis un-der different treatments were compared.ResultThree days after smearing the leaf of B. parachinensis with PAHs,the re-sults showed that the content of PAHs was 127.28 μg/kgDW,which was significantly higher than that of root hydroponic treatment(13.63 μg/kgDW)(P<0.05,the same below). PAHs mainly entered B. parachinensis through its leaf. In this pro-cess,the absorption of five different kinds of PAHs by the B. parachinensis were as follows:NAP>PHE>FLT>BaA>BaP. After leaf smear treatment,the single plant fresh weight was 44.94 g and soluble sugar content 175.67 μg/g,which were both significantly higher than the root of hydroponic treatment group and control group. The contents of vitamin C(Vc) and soluble protein were the highest in the root hydroponics treatment,with 21.24 mg/100 gFW and 10.76 μg/g respectively, which were significantly higher than those of the leaf smear treatment and control groups. The cellulose content in root hydroponics treatment group was the highest(10.26%),significantly higher than that in the control group. Both PAHs treatments had no significant effects on the chlorophyll content of B. parachinensis(P>0.05). The results of correlation analysis showed that the content of PAHs in B. parachinensis was positively correlated with single plant weight,soluble sugar content,soluble protein content and cellulose content,but negatively correlated with Vc content.ConclusionThe capacity to absorb PAHs of leaf of B. parachinensis is much stronger than the root. Therefore,during the production pro-cess,the vegetable field should be far away from roads and factories in order to prevent PAHs in exhaust gas,dust and smoke from entering B. parachinensis body through leaves,thus affecting the quality and safety of B. parachinensis.