Seasonal and within-plant gradients in the intramolecular carbon isotopic composition of amino acids of Spartina alterniflora

William B. Savidge*, Neal E. Blair

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Autotrophy and heterotrophy create different patterns of carbon flux through the central metabolic pathway. One consequence of these different fluxes is that the α-carboxyl carbon of amino acids is derived from different carbon sources and has a different isotopic composition under autotrophic and heterotrophic conditions. In Spartina alterniflora, a C4 grass and a common and ecologically important component of coastal ecosystems, the isotopic composition of bulk acid hydrolyzable carbon and total amino acid carboxyl carbon were compared over a seasonal cycle. The isotopic composition of plants varied significantly between aboveground and below ground tissues, and the δ13C of both hydrolyzable organic carbon and total amino acid carboxyl carbon showed significant variation among seasons. The isotopic heterogeneity within amino acids was used to infer seasonal changes in source/sink relationships for amino acid carbon among plant organs. Comparison of the intramolecular isotope data for Spartina and C3 freshwater marsh plants indicates that the patterns and processes inferred for Spartina are not unique to this taxon.

Original languageEnglish (US)
Pages (from-to)151-167
Number of pages17
JournalJournal of Experimental Marine Biology and Ecology
Volume308
Issue number2
DOIs
StatePublished - Sep 22 2004

Keywords

  • Amino acids
  • Nitrogen
  • Spartina alterniflora
  • Stable isotopes
  • TCA cycle
  • Translocation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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