Abstract Complex environmental interactions may modify toxicity of metals. We studied responses of the common medicinal plant chamomile to lead (Pb) toxicity under nitrate sufficient (+N) or deficient (–N) conditions involving also inhibitor of the key phenolic enzyme phenylalanine ammonia-lyase (2-aminoindane-2-phosphonic acid, AIP). Data indicate that N deficiency depleted nitrogenous but elevated phenolic metabolites or peroxidase activity and enhanced ROS (but not nitric oxide) formation evoked by Pb or AIP. Pb stimulated individual phenolic acids in the shoots but had no impact on total soluble phenols or flavonols where the impacts of AIP and N nutrition were more evident. Pb rather affected glutathione while N deficiency ascorbic and malic acids and the involvement of AIP in these changes was visible. PCA analyses showed clear separation with respect to N deficiency or AIP application. Besides, application of AIP stimulated accumulation of Pb in shoots and in absorbed root fraction while N deficiency suppressed Pb amount in shoots and stimulated in roots. Our data, to our knowledge for the first time, confirm that uptake of metals is not only a simple function of its presence but that mineral nutrition and state of the secondary metabolism have crucial impact on resulting responses.

中文翻译：

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铅的吸收和植物毒性受硝酸盐营养和酚类代谢的影响

摘要 复杂的环境相互作用可能会改变金属的毒性。我们研究了常见药用植物洋甘菊在硝酸盐充足 (+N) 或缺乏 (-N) 条件下对铅 (Pb) 毒性的反应，还涉及关键酚类酶苯丙氨酸解氨酶（2-氨基茚-2-膦酸）的抑制剂, AIP)。数据表明，N 缺乏消耗了含氮但提高了酚类代谢物或过氧化物酶活性，并增加了由 Pb 或 AIP 引起的 ROS（但不是一氧化氮）的形成。Pb 刺激了枝条中的单个酚酸，但对总可溶性酚或黄酮醇没有影响，其中 AIP 和 N 营养的影响更为明显。Pb 影响谷胱甘肽，而 N 缺乏抗坏血酸和苹果酸和 AIP 在这些变化中的参与是可见的。PCA 分析表明，N 缺乏或 AIP 应用有明显的区别。此外，AIP 的施用刺激了 Pb 在地上部和吸收根部分的积累，而 N 缺乏抑制了地上部中 Pb 的含量并刺激了根中的 Pb 含量。据我们所知，我们的数据首次证实，金属的吸收不仅是其存在的简单函数，而且矿物质营养和次级代谢状态对产生的反应具有至关重要的影响。