Abstract
The presence of water-soluble compounds in sectioned plant tissue can be visualized in negative contrast by freeze-substitution in acetone, followed by embedment in Epon containing 6% Sudan B. The contents of mature sieve tubes and companion cells of bean (Phaseolus vulgaris L.) showed strong, and mostly uniform, negative staining. The degree of negative staining was measured by microspectrophotometry. Since, in sieve tubes, virtually all of the solute is the translocated sugar, the sugar concentration can be estimated by comparison with similar measurements made on sections from pith blocks which were infiltrated with sugar solutions and processed by the same procedures. Sieve tubes contained a solution of about 11.2% (w/v) sucrose; companion cells contained a similar concentration of sucrose. Negative staining, and therefore the sucrose concentration, in immature sieve-tube elements and companion cells was much less than in their mature counterparts.
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References
Biddulph, O., Cory, R.: Translocation of C14-metabolites in the phloem of the bean plant. Plant Physiol. 40, 119–129 (1965)
Canny, M.J.: Phloem Translocation London: Cambridge University Press 1973
Dixon, A.G.F.: Aphids and translocation. In: Transport in Plants. I. Phloem Transport, pp. 154–170, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds., vol. 1. Berlin-Heidelberg-New York: Springer 1975
Eschrich, W.E.: Sealing systems in phloem. In: Transport in Plants. I. Phloem Transport, pp. 49–56, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds., vol. 1. Berlin-Heidelberg-New York: Springer 1975
Fisher, D.B.: Translocation kinetics of photosynthates. In: Phloem Transport, pp. 327–338, Aronoff, S., Dainty, J., Gorham, P.R., Srivastava, Swanson, C.A., eds., New York: Plenum Press 1972
Fisher, D.B.: Artifacts in the embedment of water-soluble compounds for light microscopy. Plant Physiol. 49, 161–165 (1972)
Fisher, D.B.: Structure of functional soybean sieve elements. Plant Physiol. 56, 555–569 (1975)
Fisher, D.B.: Histochemical approaches to water-soluble compounds and their application to problems in translocation. In: Transport and Transfer Processes in Plants, pp. 237–246, Wardlaw, I.F., Passioura, J.B., eds. New York: Academic Press 1976
Fisher, D.B., Housley, T.L.: The retention of water-soluble compounds during freeze-substitution and microautoradiography. Plant Physiol. 49, 166–171 (1972)
Fritz, E., Eschrich, W.: 14C-Mikroautoradiographie der wasserlöslichen Substanzen im Phloem. Planta 92, 267–281 (1970)
Housley, T.L., Fisher, D.B.: Estimation of osmotic gradients in soybean sieve tubes. Qualified support for the Münch hypothesis. Plant Physiol. 59, 701–706 (1977)
Milburn, J.A.: Pressure flow. In: Transport in Plants. I. Phloem Transport, pp. 328–353, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds., vol.1, Berlin-Heidelberg-New York: Springer 1975
Pate, J.A.: Exchange of solutes between phloem and xylem and circulation of solutes in the whole plant. In: Transport in Plants. I. Phloem Transport, pp. 451–473, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds., vol. 1. Berlin-Heidelberg-New York: Springer 1975
Peel, A.J.: Investigations with aphid stylets into the physiology of the sieve tube. In: Transport in Plants. I. Phloem Transport, pp. 171–195, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol. N.S., Pirson, A., Zimmermann, M.H., eds. vol. 1, Berlin-Heidelberg-New York: Springer 1975
Spurr, A.R.: A low-viscosity embedding medium for electron microscopy. J. Ultrastruct. Res. 23, 31–43 (1969)
van Die, J., Tammes, P.M.L.: Phloem exudation from monocotyledonous axes. In: Transport in Plants. I. Phloem Transport, pp. 196–222, Zimmermann, M.H., Milburn, J.A., eds. Encycl Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds., vol. 1. Berlin-Heidelberg-New York: Springer 1975
Ziegler, H.: Nature of substances in phloem. Nature of transported substances. In: Transport in Plants. I. Phloem Transport, pp. 59–100, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds. vol. 1. Berlin-Heidelberg-New York: Springer 1975
Zimmermann, M.H., Ziegler, H.: List of sugars and sugar alcohols in sieve-tube exudates. In: Transport in Plants. I. Phloem Transport, pp. 480–503, Zimmermann, M.H., Milburn, J.A., eds. Encycl. Plant Physiol., N.S., Pirson, A., Zimmermann, M.H., eds., vol. 1. Berlin-Heidelberg-New York: Springer 1975
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Fisher, D.B. The estimation of sugar concentration in individual sieve-tube elements by negative staining. Planta 139, 19–24 (1978). https://doi.org/10.1007/BF00390804
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DOI: https://doi.org/10.1007/BF00390804