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. 1992 Aug;99(4):1540–1545. doi: 10.1104/pp.99.4.1540

Sugar Uptake and Metabolism in the Developing Endosperm of Tassel-seed Tunicate (Ts-5 Tu) Maize

Paul A Thomas 1,2,1, Frederick C Felker 1,2, C Gerald Crawford 1,2,2
PMCID: PMC1080660  PMID: 16669071

Abstract

Factors regulating assimilate transport into developing maize (Zea mays L.) kernels have been difficult to determine because of the structural complexity of basal kernel tissues and the damage that results from tissue dissection. The sensitivity of maize kernels to experimental manipulation is such that substantial maternal tissue is required to support kernel growth in vitro. Consequently, sugar transport experiments with isolated seed tissues or detached kernels have not unequivocally demonstrated how sugar transport occurs. In the present study, Tassel-seed Tunicate (Ts-5 Tu) maize kernels were investigated as a model system for introducing test solutions into the pedicel apoplast with minimal wounding. Transpiration in leafy glumes drew 14C-sugar solutions up the 8- to 10-millimeter-long pedicel stalks into the basal endosperm transfer cell region. 14C from fructose was incorporated into starch for 8 days. Sugar uptake into endosperm and embryo tissue showed specificity and inhibitor sensitivity. In particular, p-chloromercuribenzene sulfonate partially inhibited fructose uptake into the endosperm but had no effect on the metabolic conversion of that fructose that entered the endosperm. These results are consistent with active, carrier-mediated sugar transport, but a definitive determination would require more detailed tissue analysis. We propose that further refinement of the incubation solution may allow long-term kernel growth without cob tissue and thus provide a more precise determination of which maternal factors influence seed development.

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Selected References

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

  1. Cully D. E., Gengenbach B. G., Smith J. A., Rubenstein I., Connelly J. A., Park W. D. Endosperm Protein Synthesis and l-[S]Methionine Incorporation in Maize Kernels Cultured In Vitro. Plant Physiol. 1984 Feb;74(2):389–394. doi: 10.1104/pp.74.2.389. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Felker F. C., Shannon J. C. Movement of C-labeled Assimilates into Kernels of Zea mays L: III. AN ANATOMICAL EXAMINATION AND MICROAUTORADIOGRAPHIC STUDY OF ASSIMILATE TRANSFER. Plant Physiol. 1980 May;65(5):864–870. doi: 10.1104/pp.65.5.864. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Giaquinta R. Evidence for Phloem loading from the apoplast: chemical modification of membrane sulfhydryl groups. Plant Physiol. 1976 Jun;57(6):872–875. doi: 10.1104/pp.57.6.872. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Griffith S. M., Jones R. J., Brenner M. L. In Vitro Sugar Transport in Zea mays L. Kernels : I. Characteristics of Sugar Absorption and Metabolism by Developing Maize Endosperm. Plant Physiol. 1987 Jun;84(2):467–471. doi: 10.1104/pp.84.2.467. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Lin W., Schmitt M. R., Hitz W. D., Giaquinta R. T. Sugar transport in isolated corn root protoplasts. Plant Physiol. 1984 Dec;76(4):894–897. doi: 10.1104/pp.76.4.894. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Peterson C. A., Griffith M., Huner N. P. Permeability of the suberized mestome sheath in winter rye. Plant Physiol. 1985 Jan;77(1):157–161. doi: 10.1104/pp.77.1.157. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Porter G. A., Knievel D. P., Shannon J. C. Sugar Efflux from Maize (Zea mays L.) Pedicel Tissue. Plant Physiol. 1985 Mar;77(3):524–531. doi: 10.1104/pp.77.3.524. [DOI] [PMC free article] [PubMed] [Google Scholar]

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