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On the mechanism of reinitiation of endogenous crassulacean acid metabolism rhythm by temperature changes

Grams, Thorsten ; Borland, Anne M. ; Roberts, Andrew ; Griffiths, Howard ; Beck, Friedrich ; Lüttge, Ulrich (1997)
On the mechanism of reinitiation of endogenous crassulacean acid metabolism rhythm by temperature changes.
In: Plant Physiology, 113 (4)
doi: 10.1104/pp.113.4.1309
Article, Bibliographie

Abstract

Plant Physiol. (1 997) 11 3 : 1309-1 31 7 On the Mechanism of Reinitiation of Endogenous Crassulacean Acid Metabolism Rhythm by Temperature Changes' Thorsten Erhard Edgar Grams2*, Anne M. Borland, Andrew Roberts, Howard Griffiths, Friedrich Beck, and Ulrich Lüttge lnstitut für Botanik, Technische Hochschule Darmstadt, Schnittspahnstrasse 3-5, 0-64287 Darmstadt, Germany (T.E.E.G., U.L.); Department of Agricultura1 and Environmental Science, Ridley Building, University of Newcastle upon Tyne, NEI 7RU, United Kingdom (A.M.B., A.R., H.C.); and lnstitut für Kernphysik, Technische Hochschule Darmstadt, Schlossgartenstrasse9, D-64289 Darmstadt, Germany (F.B.) Under continuous light the endogenous Crassulacean acid me- tabolism (CAM) rhythm of Kalanchoe daigremontiana Hamet et Perrier de Ia Bâthie disappears at high (>29.0"C) or low (<8.0"C) temperatures. We investigated the reinitiation of rhythmicity when temperature was reduced from above the upper and increased from below the lower threshold leve1 via measurements of (a) short-term changes in carbon-isotope discrimination to illustrate shifts be- tween C, and C, carboxylation in vivo, and (b) the malate sensitivity of phosphoenolpyruvate carboxylase (PEPC) in vitro. When the net C0,-exchange rhythm disappears at both temperatures, the instan- taneous discrimination indicates low PEPC activity. Leaf malate concentration and osmolarity attain high and low values at low and high temperatures, respectively. After small temperature increases or reductions from the iow and high temperatures, respectively, the rhythm is reinitiated, with phases shifted by 180" relative to each other. This can be related to the contrasting low and high leaf malate concentrations due t o direct inhibition of PEPC and possibly also of the phosphorylation of PEPC by malate. The experimental results were satisfactorily simulated by a mathematical CAM-cycle model, with temperature acting only on the passive efflux of malate from the vacuole. We stress the important role of the tonoplast i n malate compartmentation and of malate itself for the reinitiation and generation of endogenous CAM rhythmicity.

Item Type: Article
Erschienen: 1997
Creators: Grams, Thorsten ; Borland, Anne M. ; Roberts, Andrew ; Griffiths, Howard ; Beck, Friedrich ; Lüttge, Ulrich
Type of entry: Bibliographie
Title: On the mechanism of reinitiation of endogenous crassulacean acid metabolism rhythm by temperature changes
Language: English
Date: 1 April 1997
Publisher: American Society of Plant Biologists
Journal or Publication Title: Plant Physiology
Volume of the journal: 113
Issue Number: 4
DOI: 10.1104/pp.113.4.1309
Abstract:

Plant Physiol. (1 997) 11 3 : 1309-1 31 7 On the Mechanism of Reinitiation of Endogenous Crassulacean Acid Metabolism Rhythm by Temperature Changes' Thorsten Erhard Edgar Grams2*, Anne M. Borland, Andrew Roberts, Howard Griffiths, Friedrich Beck, and Ulrich Lüttge lnstitut für Botanik, Technische Hochschule Darmstadt, Schnittspahnstrasse 3-5, 0-64287 Darmstadt, Germany (T.E.E.G., U.L.); Department of Agricultura1 and Environmental Science, Ridley Building, University of Newcastle upon Tyne, NEI 7RU, United Kingdom (A.M.B., A.R., H.C.); and lnstitut für Kernphysik, Technische Hochschule Darmstadt, Schlossgartenstrasse9, D-64289 Darmstadt, Germany (F.B.) Under continuous light the endogenous Crassulacean acid me- tabolism (CAM) rhythm of Kalanchoe daigremontiana Hamet et Perrier de Ia Bâthie disappears at high (>29.0"C) or low (<8.0"C) temperatures. We investigated the reinitiation of rhythmicity when temperature was reduced from above the upper and increased from below the lower threshold leve1 via measurements of (a) short-term changes in carbon-isotope discrimination to illustrate shifts be- tween C, and C, carboxylation in vivo, and (b) the malate sensitivity of phosphoenolpyruvate carboxylase (PEPC) in vitro. When the net C0,-exchange rhythm disappears at both temperatures, the instan- taneous discrimination indicates low PEPC activity. Leaf malate concentration and osmolarity attain high and low values at low and high temperatures, respectively. After small temperature increases or reductions from the iow and high temperatures, respectively, the rhythm is reinitiated, with phases shifted by 180" relative to each other. This can be related to the contrasting low and high leaf malate concentrations due t o direct inhibition of PEPC and possibly also of the phosphorylation of PEPC by malate. The experimental results were satisfactorily simulated by a mathematical CAM-cycle model, with temperature acting only on the passive efflux of malate from the vacuole. We stress the important role of the tonoplast i n malate compartmentation and of malate itself for the reinitiation and generation of endogenous CAM rhythmicity.

Divisions: 10 Department of Biology
Date Deposited: 19 Nov 2008 15:54
Last Modified: 11 Aug 2023 14:11
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