Abstract：
Crop contamination of perfluoroalkyl substances (PFASs) may threaten human health, with root and leaves representing the primary uptake pathways of PFASs in crops. Therefore, it is imperative to elucidate the uptake characteristics of PFASs by crop roots and leaves as well as the critical influencing factors. In this study, the uptake and translocation of PFASs by roots and leaves of pak choi and radish were systematically explored based on perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS). Additionally, the roles of root Casparian strips, leaf stomata, and PFAS structures in the aforementioned processes were elucidated. Compared with pak choi, PFASs are more easily transferred to leaves after root uptake in radish, resulting from the lack of root Casparian strips. In pak choi root, the bioaccumulation of C4-C8 perfluoroalkyl carboxylic acids (PFCAs) showed a U-shaped trend with the increase of their carbon chain lengths, and the translocation potentials of individual PFASs from root to leaves negatively correlated with their chain lengths. The leaf uptake of PFOA in pak choi and radish mainly depended on cuticle sorption, with the evidence of a slight decrease in the concentrations of PFOA in exposed leaves after stomatal closure induced by abscisic acid. The leaf bioaccumulation of C4-C8 PFCAs in pak choi exhibited an inverted U-shaped trend as their carbon chain lengths increased. PFASs in exposed leaves can be translocated to the root and then re-transferred to unexposed leaves in vegetables. The longer-chain PFASs showed higher translocation potentials from exposed leaves to root. PFOS demonstrated a higher bioaccumulation than PFOA in crop roots and leaves, mainly due to the greater hydrophobicity of PFOS. Planting root vegetables lacking Casparian strips is inadvisable in PFAS-contaminated environments, in view of their higher PFAS bioaccumulation and considerable human intake.
摘要：
全氟烷基物质（PFASs）的作物污染可能威胁人类健康，根和叶代表作物中PFAS的主要吸收途径。因此,阐明作物根和叶对PFASs的吸收特性以及关键影响因素势在必行。在这项研究中,基于全氟丁酸（PFBA），系统地探索了小白菜和萝卜的根和叶对PFASs的吸收和转运，全氟己酸（PFHxA），全氟辛酸（PFOA），和全氟辛烷磺酸(PFOS)。此外,根卡斯帕里条带的作用，叶气孔,阐明了上述过程中的PFAS结构。与小白菜相比，萝卜根吸收后，PFAS更容易转移到叶片中，由于缺乏根卡斯帕里安条。在白菜根，C4-C8全氟烷基羧酸(PFCAs)的生物蓄积性随着碳链长度的增加呈U型趋势,单个PFAS从根到叶的易位电位与其链长呈负相关。小白菜和萝卜叶片对PFOA的吸收主要取决于角质层的吸收，有证据表明，脱落酸诱导的气孔关闭后，暴露叶片中PFOA的浓度略有降低。随着碳链长度的增加，小白菜中C4-C8PFCA的叶片生物积累呈倒U型趋势。暴露叶片中的PFAS可以转移到根部，然后再转移到蔬菜中未暴露的叶片中。较长链的PFAS从暴露的叶子到根显示出更高的易位潜力。全氟辛烷磺酸在作物根和叶中表现出比全氟辛烷磺酸更高的生物积累，主要是由于全氟辛烷磺酸的疏水性较大。在受PFAS污染的环境中，不建议种植缺乏卡斯帕里安条的根茎类蔬菜。鉴于它们较高的PFAS生物积累和相当大的人类摄入量。
