Abstract
The minimum radial translocation rate of sugars has been determined from the starchaccumulation rate for the wood rays of Populus x canadensis Moench ‘robusta’, and related to ultrastructural peculiarities of the cell walls to be passed. The minimum radial flux or flow of sugars through the tangential walls, the pit fields, and per plasmodesma was 80.7 pmol · cm-2 · s-1, 400 to 800 pmol · cm-2 · s-1, and 1.0 to 1.7 · 10-7 pmol · plasmodesma-1 · s-1, respectively. These values exclude a transmembrane flux mechanism and indicate that the radial translocation in this tissue must proceed via plasmodesmata. In the isolation cells of the ray center we found 39 plasmodesmata per μm2 of pit field, 8.0 per μm2 of tangential wall, and 1.98% of the wall occupied by plasmodesmata. Cells of the ray margins show plasmodesmata on only 1.16% of their tangential wall area and thus appear to be slightly inferior for radial translocation. As judged from both the observed plasmodesmatal frequencies and the translocation rates, the ray parenchyma cells are comparable to cells specialized in short-distance translocation.
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Abbreviations
- CCR:
-
contact-cell row
- IC:
-
isolation cell
- ICR:
-
isolation-cell row
References
Anderson, W.P. (1976) Physico-chemical assessment of plasmodesmatal transport. In: Intercellular communication in plants: studies on plasmodesmata, pp. 107–129, Gunning, B.E.S., Robards, A.W., eds. Springer, Berlin Heidelberg New York
Beutler, H.-O. (1978) Enzymatische Bestimmung von Stärke mit Hilfe der Hexokinase-Methode. Stärke 30, 309–312
Braun, H.J. (1970) Funktionelle Histologie der sekundären Sproßachse. I. Das Holz. In: Handbuch der Pflanzenanatomie, vol. IX, pt. 1, pp. 1–190, Zimmermann, W., Ozenda, P., Wulff, H.D., eds. Gebrüder Bornträger, Berlin Stuttgart
Giaquinta, R.T. (1983) Phloem loading of sucrose. Annu. Rev. Plant Physiol. 34, 347–387
Gunning, B.E.S. (1976) The role of plasmodesmata in short distance transport to and from the phloem. In: Intercellular communication in plants: studies on plasmodesmata, pp. 203–227, Gunning, B.E.S., Robards, A.W., eds. Springer, Berlin Heidelberg New York
Gunning, B.E.S., Robards, A.W. (1976) Plasmodesmata: curent knowledge and outstanding problems. In: Intercellular communication in plants: studies on plasmodesmata, pp. 297–311, Gunning, B.E.S., Robards, A.W., eds. Springer, Berlin Heidelberg New York
Hayes, P.M., Offler, C.E., Patrick, J.W. (1985) Cellular structure, plasma membrane surface areas and plasmodesmatal frequencies of the stem of Phaseolus vulgaris L. in relation to radial photosynthate transfer. Ann. Bot. 56, 125–138
Kuo, J., O'Brien, T.P., Canny, M.J. (1974) Pit-field distribution, plasmodesmatal frequency, and assimilate flux in mestome sheath cells of wheat leaves. Planta 121, 97–118
Lüttge, U., Higinbotham, N. (1979) Transport in plants. Springer, Berlin Heidelberg New York
MacRobbie, E.A.C. (1971) Phloem translocation, facts and mechanisms: a comparative survey. Biol. Rev. Cambridge 46, 429–481
Robards, A.W. (1976) Plasmodesmata in higher plants. In: Intercellular communication in plants: studies on plasmodesmata, pp. 15–57, Gunning, B.E.S., Robards, A.W., eds. Springer, Berlin Heidelberg New York
Sauter, J.J. (1966) Untersuchungen zur Physiologie der Pappelholzstrahlen. I. Jahresperiodischer Verlauf der Stärkespeicherung im Holzstrahlparenchym. Z. Pflanzenphysiol. 55, 246–258
Sauter, J.J. (1972) Respiratory and phosphatase activities in contact cells of wood rays and their possible role in sugar secretion. Z. Pflanzenphysiol. 67, 135–145
Sauter, J.J. (1982a) Transport in Markstrahlen. Ber. Dtsch. Bot. Ges. 95, 593–618
Sauter, J.J. (1982b) Efflux and reabsorption of sugars in the xylem. I. Seasonal changes in sucrose efflux in Salix. Z. Pflanzenphysiol. 106, 325–336
Tyree, M.T. (1970) The symplast concept. A general theory of symplastic transport according to the thermodynamics of irreversible processes. J. Theor. Biol. 26, 181–214
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Sauter, J.J., Kloth, S. Plasmodesmatal frequency and radial translocation rates in ray cells of poplar (Populus x canadensis Moench ‘robusta’). Planta 168, 377–380 (1986). https://doi.org/10.1007/BF00392363
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DOI: https://doi.org/10.1007/BF00392363