Nitrogen deficiency induced changes of free amino acids and coumarin contents in the leaves of Matricaria chamomilla |
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Authors: | Jozef Ková ik Miroslav Rep ák Ivan Korn |
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Institution: | (1) Department of Botany, Institute of Biology and Ecology, Faculty of Science, P. J. Šafárik University, Mánesova 23, 041 67 Košice, Slovak Republic;(2) Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, P. J. Šafárik University, Tr. SNP 1, 040 66, Košice, Slovak Republic |
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Abstract: | Through o-hydroxycinnamic acids, the biosynthesis of coumarins is connected with aromatic amino acid metabolism and nitrogen uptake.
Therefore the quantitative changes in levels of some free amino acids and coumarins (herniarin and its glucosidic precursors
(Z) - and (E)-2-β-D-glucopyranosyloxy-4-methoxycinnamic acids; umbelliferone) in the leaf rosettes of chamomile (Matricaria chamomilla L.) subjected to nitrogen deficiency were studied. Nitrogen content decreased in the leaf rosettes and in the roots of N-deficient
plants during the course of the experiment, but these plants produced significantly higher root biomass. Among secondary metabolites,
the sum of 2-β-D-glucopyranosyloxy-4-methoxycinnamic acids increased sharply, herniarin increased slowly and the content of umbelliferone
was low in N-deficient plants. We have concluded that nitrogen deficiency is not an inducing factor for stress accumulation
of herniarin and umbelliferone. A decrease in levels of all detected amino acids, besides histidine, was found. Within aromatic
amino acids, tyrosine was the most abundant. The content of free phenylalanine was significantly lower in both, control and
N-deficient plants when compared to the content of tyrosine. In this view, the increase of herniarin glucosidic precursors
is apparently due to enhancing phenylalanine ammonia-lyase activity under nitrogen deficiency and nitrogen-free carbon skeletons
are shunted in to the phenylpropanoid metabolism, including biosynthesis of (Z)-and (E)-2-β-D-glucopyranosyloxy-4-methoxycinnamic acids. |
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Keywords: | 2-β -D-glucopyranosyloxy-4-methoxycinnamic acids free amino acids herniarin Matricaria chamomilla nitrogen deficiency tyrosine |
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