Abstract.
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.
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Persson, J., Näsholm, T. Regulation of amino acid uptake in conifers by exogenous and endogenous nitrogen. Planta 215, 639–644 (2002). https://doi.org/10.1007/s00425-002-0786-5
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DOI: https://doi.org/10.1007/s00425-002-0786-5