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. 1986 Oct;82(2):468–472. doi: 10.1104/pp.82.2.468

Glyphosate Inhibits Photosynthesis and Allocation of Carbon to Starch in Sugar Beet Leaves 1

Donald R Geiger 1, Shelly W Kapitan 1, Michelle A Tucci 1
PMCID: PMC1056142  PMID: 16665053

Abstract

Application of glyphosate (N-[phosphonomethyl] glycine) to exporting leaves of sugar beet (Beta vulgaris, L.) during the day lowered stomatal conductance and carbon fixation. Allocation of newly fixed carbon to foliar starch accumulation was nearly completely inhibited, being decreased by the same amount as net carbon fixation. In contrast, decreasing net carbon fixation in untreated leaves by lowering CO2 concentration caused starch accumulation to decrease, but only in the same proportion as net carbon fixation. Shikimate level increased 50-fold in treated leaves but the elevated rate of carbon accumulation in shikimate was only 4% of the decrease in the rate of starch accumulation. Application of steady state labeling with 14CO2 to exporting leaves confirmed the above changes in carbon metabolism, but revealed no other major daytime differences in the 14C-content of amino acids or other compounds between treated and control leaves. Less 14C accumulated in treated leaves because of decreased fixation, not increased export. The proportion of newly fixed carbon allocated to sucrose increased, maintaining export at the level in control leaves. Returning net carbon exchange to the rate before treatment restored starch accumulation fully and prevented a decrease in export during the subsequent dark period.

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Selected References

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

  1. Amrhein N., Deus B., Gehrke P., Steinrücken H. C. The Site of the Inhibition of the Shikimate Pathway by Glyphosate: II. INTERFERENCE OF GLYPHOSATE WITH CHORISMATE FORMATION IN VIVO AND IN VITRO. Plant Physiol. 1980 Nov;66(5):830–834. doi: 10.1104/pp.66.5.830. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Brecke B. J., Duke W. B. Effect of Glyphosate on Intact Bean Plants (Phaseolus vulgaris L.) and Isolated Cells. Plant Physiol. 1980 Oct;66(4):656–659. doi: 10.1104/pp.66.4.656. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Fondy B. R., Geiger D. R. Diurnal Pattern of Translocation and Carbohydrate Metabolism in Source Leaves of Beta vulgaris L. Plant Physiol. 1982 Sep;70(3):671–676. doi: 10.1104/pp.70.3.671. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Geiger D. R., Fondy B. R. A method for continuous measurement of export from a leaf. Plant Physiol. 1979 Sep;64(3):361–365. doi: 10.1104/pp.64.3.361. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Laberke H. G., Baur R. Der normale proximale Ureter des Menschen. Methodik der Histomorphometrie und Ergebnisse. Urologe A. 1986 Jul;25(4):238–240. [PubMed] [Google Scholar]
  6. Outlaw W. H., Manchester J. Guard cell starch concentration quantitatively related to stomatal aperture. Plant Physiol. 1979 Jul;64(1):79–82. doi: 10.1104/pp.64.1.79. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Redgwell R. J. Fractionation of plant extracts using ion-exchange Sephadex. Anal Biochem. 1980 Sep 1;107(1):44–50. doi: 10.1016/0003-2697(80)90489-3. [DOI] [PubMed] [Google Scholar]
  8. Rubin J. L., Gaines C. G., Jensen R. A. Enzymological basis for herbicidal action of glyphosate. Plant Physiol. 1982 Sep;70(3):833–839. doi: 10.1104/pp.70.3.833. [DOI] [PMC free article] [PubMed] [Google Scholar]

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