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Media type:
E-Article
Title:
Regulation of amino acid uptake in conifers by exogenous and endogenous nitrogen
Contributor:
Persson, Jörgen;
Näsholm, Torgny
Published:
Springer-Verlag, 2002
Published in:
Planta, 215 (2002) 4, Seite 639-644
Language:
English
ISSN:
0032-0935;
1432-2048
Origination:
Footnote:
Description:
Although an accumulating amount of research clearly indicates that plants are capable of taking up exogenous amino acids, the actual importance of such organic N sources for plant N nutrition is under debate. In this study, we show that amino acid uptake by Scots pine (Pinus sylvestris L.) is significantly decreased by elevated internal NH4+ levels, while it increases following exposure to exogenous amino acids. Furthermore, amino acid uptake is larger in N-deficient plants than in plants grown with a large access of N. The regulatory pattern of amino acid uptake shows important similarities to the regulation of NO3- and NH4+ transport as well as to the regulation of yeast amino acid transporters. In addition, our data suggest that uptake may be regulated by factors not originating from N metabolism. The up-regulation of uptake in response to N deficiency suggests that amino acid uptake may be a significant contributor to the N economy of P. sylvestris.