Department of Botany, Institute of Biology and Ecology, Faculty of Science, P J Šafárik University, Košice, Slovak Republic.
J Agric Food Chem. 2011 May 11;59(9):5139-49. doi: 10.1021/jf104793b. Epub 2011 Apr 14.
The effect of nitrogen (nitrate) deficiency (-N) on the accumulation of cadmium (Cd) and nickel (Ni) in chamomile ( Matricaria chamomilla ) plants was studied. Elimination of N from the culture medium led to decreases in N-based compounds (free amino acids and soluble proteins) and increases in C-based compounds (reducing sugars, soluble phenols, coumarins, phenolic acids, and partially flavonoids and lignin), being considerably affected by the metal presence. Proline, a known stress-protective amino acid, decreased in all -N variants. The activity of phenylalanine ammonia-lyase was stimulated only in -N control plants, whereas the activities of polyphenol oxidase and guaiacol peroxidase were never reduced in -N variants in comparison with respective +N counterparts. Among detected phenolic acids, chlorogenic acid strongly accumulated in all N-deficient variants in the free fraction and caffeic acid in the cell wall-bound fraction. Mineral nutrients were rather affected by a given metal than by N deficiency. Shoot and total root Cd and Ni amounts decreased in -N variants. On the contrary, ammonium-fed plants exposed to N deficiency did not show similar changes in Cd and Ni contents. The present findings are discussed with respect to the role of phenols and mineral nutrition in metal uptake.
研究了氮（硝酸盐）缺乏（-N）对甘菊（Matricaria chamomilla）植物中镉（Cd）和镍（Ni）积累的影响。从培养基中去除 N 会导致基于 N 的化合物（游离氨基酸和可溶性蛋白质）减少，而基于 C 的化合物（还原糖、可溶性酚类、香豆素、酚酸以及部分类黄酮和木质素）增加，这些变化受到金属存在的显著影响。脯氨酸是一种已知的应激保护氨基酸，在所有-N 变体中均减少。只有在-N 对照植物中，苯丙氨酸氨裂解酶的活性才受到刺激，而与相应的+N 相比，多酚氧化酶和愈创木酚过氧化物酶的活性在-N 变体中从未降低。在所检测的酚酸中，绿原酸在所有缺乏 N 的变体中均强烈积累在游离部分，咖啡酸则在细胞壁结合部分积累。与特定金属相比，矿质养分受 N 缺乏的影响更大。-N 变体中地上部和总根 Cd 和 Ni 含量减少。相反，暴露于 N 缺乏的铵喂养植物在 Cd 和 Ni 含量方面没有表现出类似的变化。目前的研究结果与酚类物质和矿物质营养在金属吸收中的作用有关。
