Journal Article

Why Abaxial Illumination Limits Photosynthetic Carbon Fixation inSpinachLeaves

Jindong Sun and JohnN. Nishio

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 42, issue 1, pages 1-8
Published in print January 2001 | ISSN: 0032-0781
Published online January 2001 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pce001
Why Abaxial Illumination Limits Photosynthetic Carbon Fixation inSpinachLeaves

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Limitations of carbon fixation within spinach leaves due to light and CO2 were investigated. Under equivalent photon fluxes, carbon fixation was higher when leaves were irradiated adaxially compared to abaxially. Maximal carbon fixation occurred in the middle of the palisade mesophyll under adaxial illumination, whereas, maximal carbon fixation occurred in the spongy mesophyll under abaxial illumination. Total carbon fixation and the pattern of carbon fixation across leaves were similar, when leaves were irradiated with 800 µmol quanta m–2 s–1 either adaxially alone or adaxially plus abaxially (1,600 µmol quanta m–2 s–1). In contrast, when both leaf surfaces were irradiated simultaneously with 200 µmol quanta m–2 s–1, total carbon fixation increased and carbon fixation in the middle of the leaf was higher compared to leaves irradiated unilaterally with the low light. Feeding 14CO2 through either the adaxial or abaxial leaf surface did not change the pattern of carbon fixation across the leaf. Increasing 14CO2 pulse-feeding times from 5 s to 60 s allowed more 14CO2 to be fixed but did not change the pattern of 14CO2 fixation across the leaf. We concluded that in spinach, the distribution of both light and Rubisco activity within leaves has significant effects on the patterns of carbon fixation across leaves; whereas CO2 diffusion does not appear to affect the carbon fixation pattern within spinach leaves.

Keywords: Key words: Carbon fixation — CO2 diffusion — Photosynthetic limitations — Rubisco — Spinacia oleracea.; Abbreviations: PM, palisade mesophyll; Rubisco, Ribulose-1,5-bisphosphate carboxylase/oxygenase; SM, spongy mesophyll.

Journal Article.  6269 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.