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. 1977 Jan;135(3):297-9.
doi: 10.1007/BF00384903.

Proton co-transport of sugars in phloem loading

F Malek  1 , D A Baker
Affiliations

Proton co-transport of sugars in phloem loading

F Malek et al. Planta. 1977 Jan.

Abstract

Loading of (14)C-labelled sugars from the hollow petiole of Ricinus communis L. was stimulated by potassium and by low pH in that both the (14)C-activity and the sugar concentration of phloem sap collected from a nearby incision increased. A pH drop was observed in the solution perfusing a hollow petiole. This pH drop was greater in the presence of potassium and less in the presence of sugars, while the uncoupler CCCP induced a pH rise in the perfusing solution. Sugars were detected in the perfusing solution when it was buffered at pH>9. A model is proposed for a proton co-transport of sugars from the free space driven by a linked proton efflux/potassium influx pump.

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References

    1. Planta. 1972 Jun;106(2):131-40 - PubMed
    1. J Ultrastruct Res. 1973 Sep;44(5):388-404 - PubMed
    1. FEBS Lett. 1973 Dec 15;38(1):16-8 - PubMed
    1. Biochem Biophys Res Commun. 1970 Nov 9;41(3):655-61 - PubMed

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