, Volume 171, Issue 2, pp 227–234

Evidence for a light-dependent system for reassimilation of photorespiratory CO2, which does not include a C4 cycle, in the C3−C4 intermediate species Moricandia arvensis

  • Stephen Hunt
  • Alison M. Smith
  • Harold W. Woolhouse

DOI: 10.1007/BF00391098

Cite this article as:
Hunt, S., Smith, A.M. & Woolhouse, H.W. Planta (1987) 171: 227. doi:10.1007/BF00391098


Three methods of estimating photorespiratory rate in leaves of the C3−C4 intermediate species Moricandia arvensis and the related C3 species Moricandia moricandioides were compared. The results indicated that the photorespiratory rate in M. arvensis is less than in M. moricandioides, and that this is caused partly by reduced carbon flux through the photorespiratory pathway, and partly by the presence of a mechanism for enhanced photorespiratory CO2 reassimilation in the intermediate species. Measurements of the CO2 compensation point (Γ) in the two species supported this conclusion. A functional C4 pathway is unlikely to be involved in the reduction of photorespiratory rate in M. arvensis since pulse-chase experiments showed that carbon did not move from C4 acids to the reductive pentose-phosphate pathway in attached leaves under steady-state conditions at Γ.

Key words

C3−C4 intermediate speciesC4 cycleCarbon diocide reassimilationMoricandiaPhotorespiration

Abbreviations and symbols


apparent photosynthetic rate

Ci, Ce

intercellular, external CO2 concentration


CO2 compensation point


photosynthetically active radiation


photon flux density

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Stephen Hunt
    • 1
  • Alison M. Smith
    • 1
  • Harold W. Woolhouse
    • 1
  1. 1.John Innes InstituteNorwichUK
  2. 2.Department of BiologyQueen's UniversityKingstonCanada