多环芳烃进入菜心体内的途径及其对菜心产量和品质的影响

摘要

[Objective]The 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.[Method]At 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.[Result]Three 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.[Conclusion]The 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.%[目的]探索多环芳烃(PAHs)进入菜心的主要途径,为提高菜心产量和品质及保障质量安全提供参考依据.[方法]在菜心收获期,利用5种PAHs对菜心进行叶面涂抹和根部水培处理,比较两种处理方式下菜心体内的PAHs含量、菜心产量和营养品质差异.[结果]叶面涂抹处理后3 d,菜心中的PAHs总含量为127.28 μg/kgDW,显著高于根部水培处理组(13.63 μg/kgDW)(P<0.05,下同).菜心主要以叶面吸收PAHs,此过程中菜心对5种PAHs的吸收量排序为萘>菲>荧蒽>苯并(a)蒽>苯并(a)芘.叶面涂抹处理组菜心的单株鲜重和可溶性糖含量分别为44.94 g和175.67 μg/g,均显著高于根部水培处理和对照组;维生素C(Vc)和可溶性蛋白含量以根部水培处理组最高,分别为21.24 mg/100 gFW和10.76 μg/g,均显著高于叶面涂抹处理组和对照组;根部水培处理组的纤维素含量最高,为10.26%,与对照组差异显著;两种PAHs处理方式对菜心叶绿素含量无显著影响(P>0.05).相关性分析结果表明,菜心体内的总PAHs含量与菜心单株鲜重、可溶性糖含量、可溶性蛋白含量和纤维素含量呈正相关,与Vc含量呈负相关.[结论]菜心叶面吸收PAHs的能力远强于根部,生产上菜地选择应远离公路和工厂,以避免尾气、灰尘和烟雾中的PAHs等通过叶片进入菜心体内,影响菜心品质及食用安全.