PLANT PHYSIOLOGY , Vol 108, Issue 3 913-918, Copyright © 1995 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
Control of Vascular Sap pH by the Vessel-Associated Cells in Woody Species (Physiological and Immunological Studies)
L. Fromard, V. Babin, P. Fleurat-Lessard, J. C. Fromont, R. Serrano and J. L. Bonnemain
Laboratoire de Physiologie et Biochimie Vegetales (Unite de Recherche Associee au Centre National de la Recherche Scientifique 574), Universite de Poitiers, 25 rue du Faubourg Saint-Cyprien, 86000 Poitiers, France (L.F., V.B., P.F.-L., J.-C.F., J.-L.B.)
In Robinia wood, the vessel-associated cells form a continuous sleeve
around the vessels. Variations in pH of the solution perfused through the
vessels during the annual cycle and the opposing effects of carbonyl
cyanide-m-chlorophenylhydrazone and fusicoccin on this pH value indicate
that some living cells of the wood are involved in the control of vascular
sap pH and that this control fluctuates with the seasons. The
immunolocalization of the plasma membrane HT+-ATPase in Robinia wood was
studied by the immunogold-silver-staining technique using an antibody
raised against a conserved stretch of the cytoplasmic domain of the
H+-ATPase. The immunostaining is much stronger in vessel-associated cells
than in other living cell types (ray and axial parenchyma elements) of the
secondary xylem. Our data show an efficient involvement of this cell type
in the control of vascular sap pH.
