Root and shoot respiration of perennial ryegrass are supplied by the same substrate pools: Assessment by dynamic 13C labeling and compartmental analysis of tracer kinetics

Christoph Andreas Lehmeier, Fernando Alfredo Lattanzi, Rudi Schäufele, Melanie Wild, Hans Schnyder

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

The substrate supply system for respiration of the shoot and root of perennial ryegrass (Lolium perenne) was characterized in terms of component pools and the pools' functional properties: size, half-life, and contribution to respiration of the root and shoot. These investigations were performed with perennial ryegrass growing in constant conditions with continuous light. Plants were labeled with 13CO2/12CO2 for periods ranging from 1 to 600 h, followed by measurements of the rates and 13C/12C ratios of CO2 respired by shoots and roots in the dark. Label appearance in roots was delayed by approximately 1 h relative to shoots; otherwise, the tracer time course was very similar in both organs. Compartmental analysis of respiratory tracer kinetics indicated that, in both organs, three pools supplied 95% of all respired carbon (a very slow pool whose kinetics could not be characterized provided the remaining 5%). The pools' half-lives and relative sizes were also nearly identical in shoot and root (half-life <15 min, approximately 3 h, and 33 h). An important role of short-term storage in supplying respiration was apparent in both organs: only 43% of respiration was supplied by current photosynthate (fixed carbon transferred directly to centers of respiration via the two fastest pools). The residence time of carbon in the respiratory supply system was practically the same in shoot and root. From this and other evidence, we argue that both organs were supplied by the same pools and that the residence time was controlled by the shoot via current photosynthate and storage deposition/mobilization fluxes.

Original languageEnglish
Pages (from-to)1148-1158
Number of pages11
JournalPlant Physiology
Volume148
Issue number2
DOIs
StatePublished - Oct 2008
Externally publishedYes

Fingerprint

Dive into the research topics of 'Root and shoot respiration of perennial ryegrass are supplied by the same substrate pools: Assessment by dynamic 13C labeling and compartmental analysis of tracer kinetics'. Together they form a unique fingerprint.

Cite this