Growth and maintenance respiration for individual plants in hierarchically structured canopies of Medicago sativa and Helianthus annuus: The contribution of current and old assimilates

Markus Lötscher, Katja Klumpp, Hans Schnyder

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

• Respiratory costs of Medicago sativa and Helianthus annuus individuals growing in hierarchically structured stands in a controlled environment were analysed with regard to the daily rate of carbon (C) assimilation. • Net assimilation of new C (An, g C d -1) and respiration rates of new (Rnew, g C d-1) and old C (Rold, g C d-1) were assessed by 13CO 2 labelling and gas exchange measurements. • Specific respiration rate of old C (rold, g C g-1 C d-1) decreased exponentially with increasing shoot biomass, but was not affected by the instantaneous relative growth rate (Δwi). The growth coefficient g (Rnew:An) was c. 0.32. In the most severely shaded subordinate plants, g was < 0.2, but low g stimulated rold. The contribution of Rnew to total respiraton (fR, new) and the carbon use efficiency CUE (1 - R/(An + Rnew)) were c. 0.68 and 0.62 for Δwi, > 0.1, respectively. For Δwi < 0.1, fR, new and CUE decreased with decreasing Δwi in both dominant and subordinate plants. • The results suggest that Rold was closely related to maintenance, whereas Rnew was primarily involved in growth.

Original languageEnglish
Pages (from-to)305-316
Number of pages12
JournalNew Phytologist
Volume164
Issue number2
DOIs
StatePublished - Nov 2004
Externally publishedYes

Keywords

  • C labelling
  • Carbon use efficiency
  • Gas exchange
  • Growth and maintenance respiration
  • Helianthus annuus
  • Hierarchical position
  • Medicago sativa
  • Relative growth rate

Fingerprint

Dive into the research topics of 'Growth and maintenance respiration for individual plants in hierarchically structured canopies of Medicago sativa and Helianthus annuus: The contribution of current and old assimilates'. Together they form a unique fingerprint.

Cite this