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Nitrate Deficiency Reduces Cadmium and Nickel Accumulation in Chamomile Plants
- Kovacik, Jozef, Klejdus, Borivoj, Stork, Frantisek, Hedbavny, Josef
- Journal of agricultural and food chemistry 2011 v.59 no.9 pp. 5139–5149
- Matricaria chamomilla, cadmium, caffeic acid, catechol oxidase, chamomile, chlorogenic acid, coumarins, culture media, free amino acids, nickel, nitrates, nutrients, nutrition, peroxidase, phenols, phenylalanine ammonia-lyase, reducing sugars, shoots
- 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.