Pyrrolizidine alkaloids (PAs) and their N-oxide (PANOs), as emerging environmental pollutants and chemical hazards in food, have become the focus of global attention. PAs/PANOs enter crops from soil and reach edible parts, but knowledge about their uptake and transport behavior in crops is currently limited. In this study, we chose tea ( L.) as a representative crop and Sp/SpNO as typical PAs/PANOs to analyze their root uptake and transport mechanism. Tea roots efficiently absorbed Sp/SpNO, utilizing both passive and active transmembrane pathways. Sp predominantly concentrated in roots and SpNO efficiently translocated to above-ground parts. The prevalence of SpNO in cell-soluble fractions facilitated its translocation from roots to stems and leaves. In soil experiment, tea plants exhibited weaker capabilities for the uptake and transport of Sp/SpNO compared to hydroponic conditions, likely due to the swift degradation of these compounds in the soil. Moreover, a noteworthy interconversion between Sp and SpNO in tea plants indicated a preference for reducing SpNO to Sp. These findings represent a significant stride in understanding the accumulation and movement mechanisms of Sp/SpNO in tea plants. The insights garnered from this study are pivotal for evaluating the associated risks of PAs/PANOs and formulating effective control strategies.

中文翻译：

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茶树对千叶茶碱（Sp）和千叶茶碱-N-氧化物（SpNO）的摄取、积累、易位和转化


吡咯里西啶生物碱（PAs）及其氮氧化物（PANOs）作为新兴的环境污染物和食品中的化学危害，已成为全球关注的焦点。 PA/PANO 从土壤进入作物并到达可食用部分，但目前对其在作物中的吸收和运输行为的了解有限。在本研究中，我们选择茶（L.）作为代表作物，Sp/SpNO作为典型的PAs/PANOs来分析其根部吸收和运输机制。茶根利用被动和主动跨膜途径有效吸收 Sp/SpNO。 Sp 主要集中在根部，SpNO 有效地转移到地上部分。 SpNO 在细胞可溶部分中的普遍存在促进了其从根到茎和叶的易位。在土壤实验中，与水培条件相比，茶树对 Sp/SpNO 的吸收和运输能力较弱，这可能是由于这些化合物在土壤中的快速降解所致。此外，茶树中 Sp 和 SpNO 之间值得注意的相互转化表明茶树倾向于将 SpNO 还原为 Sp。这些发现代表了理解茶树中 Sp/SpNO 的积累和运动机制的重大进步。这项研究获得的见解对于评估 PA/PANO 的相关风险和制定有效的控制策略至关重要。