Skip to main content

Some NLM-NCBI services and products are experiencing heavy traffic, which may affect performance and availability. We apologize for the inconvenience and appreciate your patience. For assistance, please contact our Help Desk at info@ncbi.nlm.nih.gov.

The Plant Cell logoLink to The Plant Cell
. 1993 Aug;5(8):953–961. doi: 10.1105/tpc.5.8.953

Carbon Fixation Gradients across Spinach Leaves Do Not Follow Internal Light Gradients.

JN Nishio 1, J Sun 1, TC Vogelmann 1
PMCID: PMC160330  PMID: 12271092

Abstract

In situ measurements of 14C-CO2 incorporation into 40-[mu]m paradermal leaf sections of sun- and shade-grown spinach leaves were determined. Chlorophyll, carotenoid, and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) content in similar 40-[mu]m paradermal leaf sections was also measured. The carbon fixation gradient did not follow the leaf internal light gradient, which decreases exponentially across the leaf. Instead, the 14C-CO2 fixation was higher in the middle of the leaf. Contrary to expectations, the distribution of carbon fixation across the leaf showed that the spongy mesophyll contributes significantly to the total carbon reduced. Approximately 60% of the carboxylation occurred in the palisade mesophyll and 40% occurred in the spongy mesophyll. Carbon reduction correlated well with Rubisco content, and no correlation between chlorophyll and carotenoid content and Rubisco was observed in sun plants. The correlation among chlorophyll, carotenoids, Rubisco, and carbon fixation was higher in shade leaves than in sun leaves. The results are discussed in relation to leaf photosynthetic and biochemical measurements that generally consider the leaf as a single homogeneous unit.

Full Text

The Full Text of this article is available as a PDF (1.1 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alberte R. S., McClure P. R., Thornber J. P. Photosynthesis in trees: organization of chlorophyll and photosynthetic unit size in isolated gymnosperm chloroplasts. Plant Physiol. 1976 Sep;58(3):341–344. doi: 10.1104/pp.58.3.341. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Chow W. S., Melis A., Anderson J. M. Adjustments of photosystem stoichiometry in chloroplasts improve the quantum efficiency of photosynthesis. Proc Natl Acad Sci U S A. 1990 Oct;87(19):7502–7506. doi: 10.1073/pnas.87.19.7502. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  4. Outlaw W. H., Fisher D. B. Compartmentation in Vicia faba Leaves: I. Kinetics of C in the Tissues following Pulse Labeling. Plant Physiol. 1975 Apr;55(4):699–703. doi: 10.1104/pp.55.4.699. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Outlaw W. H., Schmuck C. L., Tolbert N. E. Photosynthetic Carbon Metabolism in the Palisade Parenchyma and Spongy Parenchyma of Vicia faba L. Plant Physiol. 1976 Aug;58(2):186–189. doi: 10.1104/pp.58.2.186. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Plant Cell are provided here courtesy of Oxford University Press

RESOURCES