Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1985 Apr;77(4):863–868. doi: 10.1104/pp.77.4.863

Sucrose Concentration at the Apoplastic Interface between Seed Coat and Cotyledons of Developing Soybean Seeds

Roger M Gifford 1,1, John H Thorne 1,2
PMCID: PMC1064620  PMID: 16664151

Abstract

The apoplastic sucrose concentration at the interface between cotyledons and surrounding seed coats of developing soybeans (Glycine max L. Merr. cv Wye) was found by three indirect methods to be in the range of 150 to 200 millimolar. This is an order of magnitude higher than has been reported elsewhere for soybean. It was also higher than the overall sucrose concentrations in the cotyledons and seed coats, each of which was approximately 90 millimolar. By defoliating plants 24 hours before measurement, both the overall sucrose concentration in the cotyledons and the interfacial apoplastic sucrose concentration were reduced by three-fourths. However, there was no day/night difference in overall tissue sucrose concentration of cotyledons or seed coats from intact plants suggesting the existence of a homeostatic mechanism compensating for the diurnal photosynthetic cycle. About 7 hours were required for a tritiated polyethylene glycol-900 solution to fully permeate developing cotyledons (from ∼220 milligram fresh weight embryos), implying high diffusion resistance through the tissue.

These results indicate that a high interfacial sucrose concentration may exist in vivo. They suggest that the saturable carrier-mediated component of sucrose uptake may be of little physiological significance in the outermost cell layers of the cotyledons.

Full text

PDF
866

Selected References

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

  1. Bennett A. B., Spanswick R. M. Derepression of amino Acid-h cotransport in developing soybean embryos. Plant Physiol. 1983 Jul;72(3):781–786. doi: 10.1104/pp.72.3.781. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Hsu F. C., Bennett A. B., Spanswick R. M. Concentrations of sucrose and nitrogenous compounds in the apoplast of developing soybean seed coats and embryos. Plant Physiol. 1984 May;75(1):181–186. doi: 10.1104/pp.75.1.181. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Lichtner F. T., Spanswick R. M. Sucrose uptake by developing soybean cotyledons. Plant Physiol. 1981 Sep;68(3):693–698. doi: 10.1104/pp.68.3.693. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Schmitt M. R., Hitz W. D., Lin W., Giaquinta R. T. Sugar Transport into Protoplasts Isolated from Developing Soybean Cotyledons : II. Sucrose Transport Kinetics, Selectivity, and Modeling Studies. Plant Physiol. 1984 Aug;75(4):941–946. doi: 10.1104/pp.75.4.941. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Thorne J. H. Characterization of the active sucrose transport system of immature soybean embryos. Plant Physiol. 1982 Oct;70(4):953–958. doi: 10.1104/pp.70.4.953. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Thorne J. H. Morphology and ultrastructure of maternal seed tissues of soybean in relation to the import of photosynthate. Plant Physiol. 1981 May;67(5):1016–1025. doi: 10.1104/pp.67.5.1016. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Thorne J. H., Rainbird R. M. An in vivo technique for the study of Phloem unloading in seed coats of developing soybean seeds. Plant Physiol. 1983 May;72(1):268–271. doi: 10.1104/pp.72.1.268. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Zierler K. A critique of compartmental analysis. Annu Rev Biophys Bioeng. 1981;10:531–562. doi: 10.1146/annurev.bb.10.060181.002531. [DOI] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES