Uptake of nitrogen from solutions containing multiple N sources.

B. Thornton, David Robinson

Research output: Contribution to journalArticle

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Abstract

We assessed the extent to which plants can acquire amino acids when supplied as single N-sources or when plants have access to a mixture of amino- and inorganic N sources. Because the uptake of different N-sources is temperature-dependent, the effects of temperature on amino-N uptake were also tested. Lolium perenne (perennial rye-grass) was grown hydroponically at 11 degrees C or 21 degrees C. Uptake of N was determined using N-15 tracers at the growth temperature from solutions containing either nitrate, ammonium or glycine as single N sources and from a mixture containing all three N-forms. Estimates of the relative importance of amino acids such as glycine to the total N budget of plants will have been underestimated in studies where uptake was determined in single source solutions compared with those from solutions containing a mixture of N-forms. The proportion of total N acquired from the mixed N source as ammonium increased as temperature was reduced. Regarding the uptake and initial metabolism of glycine, uptake was probably the rate limiting step at 11 degrees C whilst it was the metabolism of glycine to serine at 21 degrees C. Although N-15 incorporation into the plant amino-N pool was generally in proportion to the abundance of individual amino acids, its incorporation into the glycine pool was sometimes significantly less than predicted.

Original languageEnglish
Pages (from-to)813-821
Number of pages8
JournalPlant, Cell & Environment
Volume28
DOIs
Publication statusPublished - 2005

Keywords

  • nitrate
  • ammonium
  • glycine
  • amino acids
  • temperature
  • uptake
  • mixed N solutions
  • AMINO-ACID-UPTAKE
  • BOREAL FOREST PLANTS
  • ARCTIC SALT-MARSH
  • ORGANIC NITROGEN
  • LOLIUM-PERENNE
  • NITRATE INFLUX
  • ZEA-MAYS
  • STORED N
  • AMMONIUM
  • GLYCINE

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