Perfusion of onion root xylem vessels: a method and some evidence of control of the pH of the xylem sap
Perfusion of onion root xylem vessels: a method and some evidence of control of the pH of the xylem sap
We describe a method for perfusing the xylem in the stele of excised onion roots with solutions of known composition under a pressure gradient. Tracer studies using [14C] polyethylene glycol 4000 and the fluorescent dye, Tinopal CBSX, indicated that perfusing solutions passed exclusively through the xylem vessels. The conductance of the xylem was small over the apical 100 mm of the root axis but increased markedly between 100 and 200 mm. Unbuffered perfusion solutions supplied in the range pH 3.7–7.8 emerged after passage through the xylem adjusted to pH 5.2–6.0, indicating the presence of mechanisms for absorbing or releasing protons. This adjustment continued over many hours with net proton fluxes apparently determined by the disparity between the pH of the perfusion solution and the usual xylem sap pH of about 5.5. Mild acidification of the xylem sap by buffered perfusion solutions …
361-369
Clarkson, D.T.
d642c1c3-42d4-409f-bc23-63cb18880779
Williams, Lorraine
79ee1856-3732-492b-8ac5-239749c85d9e
Hanson, J.B.
3a48c1a8-4631-45c5-93d9-147a5052432d
1 October 1984
Clarkson, D.T.
d642c1c3-42d4-409f-bc23-63cb18880779
Williams, Lorraine
79ee1856-3732-492b-8ac5-239749c85d9e
Hanson, J.B.
3a48c1a8-4631-45c5-93d9-147a5052432d
Clarkson, D.T., Williams, Lorraine and Hanson, J.B.
(1984)
Perfusion of onion root xylem vessels: a method and some evidence of control of the pH of the xylem sap.
Planta, 162 (4), .
(doi:10.1007/BF00396749).
Abstract
We describe a method for perfusing the xylem in the stele of excised onion roots with solutions of known composition under a pressure gradient. Tracer studies using [14C] polyethylene glycol 4000 and the fluorescent dye, Tinopal CBSX, indicated that perfusing solutions passed exclusively through the xylem vessels. The conductance of the xylem was small over the apical 100 mm of the root axis but increased markedly between 100 and 200 mm. Unbuffered perfusion solutions supplied in the range pH 3.7–7.8 emerged after passage through the xylem adjusted to pH 5.2–6.0, indicating the presence of mechanisms for absorbing or releasing protons. This adjustment continued over many hours with net proton fluxes apparently determined by the disparity between the pH of the perfusion solution and the usual xylem sap pH of about 5.5. Mild acidification of the xylem sap by buffered perfusion solutions …
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Published date: 1 October 1984
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Local EPrints ID: 483150
URI: http://eprints.soton.ac.uk/id/eprint/483150
ISSN: 0032-0935
PURE UUID: e5797a90-fbe4-4647-a3be-0cf37b483ccc
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Date deposited: 25 Oct 2023 16:58
Last modified: 17 Mar 2024 05:17
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Author:
D.T. Clarkson
Author:
J.B. Hanson
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