Allocation of reserve-derived and currently assimilated carbon and nitrogen in seedlings of Helianthus annuus under subambient and elevated CO2 growth conditions

Christoph A. Lehmeier, Rudi Schäufele, Hans Schnyder

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

• Here, we analysed the transition from heterotrophic to autotrophic growth of the epigeal species sunflower (Helianthus annuus), and how transition is affected by CO2. • Growth analysis and steady-state 13CO2/12CO2 and 15NO 3-/14NO3- labelling were used to quantify reserve- and current assimilation-derived carbon (C) and nitrogen (N) allocation to shoots and roots in the presence of 200 and 1000 μmol CO2 mol-1 air. • Growth was not influenced by CO2 until cotyledons unfolded. Then, C accumulation at elevated CO2 increased to a rate 2-2.5 times higher than in subambient CO 2 due to increased unit leaf rate (+ 120%) and leaf expansion (+ 60%). CO2 had no effect on mobilization and allocation of reserve-derived C and N, even during the transition period. Export of autotrophic C from cotyledons began immediately following the onset of photosynthetic activity, serving roots and shoots near-simultaneously. Allocation of autotrophic C to shoots was increased at subambient CO 2. • The synchrony in transition from heterotrophic to autotrophic supply for different sinks in sunflower contrasts with the sequential transition reported for species with hypogeal germination.

Original languageEnglish
Pages (from-to)613-621
Number of pages9
JournalNew Phytologist
Volume168
Issue number3
DOIs
StatePublished - Dec 2005
Externally publishedYes

Keywords

  • Allocation
  • C and N labelling
  • Carbon (C)
  • Helianthus annuus (sunflower)
  • Mobilization
  • Nitrogen (N)
  • Seed reserves
  • Subambient and elevated CO

Fingerprint

Dive into the research topics of 'Allocation of reserve-derived and currently assimilated carbon and nitrogen in seedlings of Helianthus annuus under subambient and elevated CO2 growth conditions'. Together they form a unique fingerprint.

Cite this