Plasma membrane H+-ATPase, succinate and isocitrate dehydrogenases activities of vessel-associated cells in walnut trees
| Autor: | Thierry Ameglio, Agnes Guillot, Jean-Louis Julien, André Lacointe, Gilles Petel, Pierrette Fleurat-Lessard, Jörg J. Sauter, Georges Alves |
|---|---|
| Přispěvatelé: | ProdInra, Archive Ouverte, Laboratoire de Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier (PIAF), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP) |
| Rok vydání: | 2001 |
| Předmět: |
0106 biological sciences
Physiology ATPase Plant Science 01 natural sciences 03 medical and health sciences chemistry.chemical_compound Proton transport [SDV.BV.PEP] Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy 030304 developmental biology FLUX DE PROTON 0303 health sciences Juglans microcarpa biology Succinate dehydrogenase Xylem biology.organism_classification [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy Isocitrate dehydrogenase Biochemistry chemistry Fusicoccin Symporter biology.protein Agronomy and Crop Science 010606 plant biology & botany |
| Zdroj: | Journal of Plant Physiology Journal of Plant Physiology, Elsevier, 2001, 158, pp.1263-1271 |
| ISSN: | 0176-1617 |
| DOI: | 10.1078/0176-1617-00503 |
| Popis: | Summary In winter and spring, walnut trees exhibit variations of sugar content in the vascular sap. According to their location, the vessel-associated cells (VACs, also called contact cells) could control nutrient exchanges between the storage parenchyma and the xylem vessels. According to the literature, the recovery of sap (influx) occurs at the VAC/vessel interface via an H+/sugar symport that depends on the transmembrane pH gradient generated by the plasma membrane H+-ATPase. The aim of this study was to investigate the ATPase activity, using a perfusion technique that allows the use of several effectors: carbonyl cyanide m-chlorophenylhydrazone (CCCP) and fusicoccin (FC). During winter, the uncoupler CCCP revealed a low pH gradient between the xylem vessels and the vessel-associated cells. Under these conditions, FC, an activator of the H+-ATPase, had no effect on the pH of the perfusion solution, suggesting that the enzyme could be lightly active. In contrast, close to bud break, a high pH gradient was revealed by the use of CCCP, and an acidification of the perfusion solution was observed in the presence of FC. Moreover, cytochemical investigation showed high activity of two respiratory enzymes located in mitochondria: NAD-dependent isocitrate dehydrogenase and succinate dehydrogenase. The hypothesis is that in spring this high respiratory activity of VACs provides a consequent increase in available ATP that can be utilized by the plasma membrane H+-ATPase. |
| Databáze: | OpenAIRE |
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