title: Involvement of plasma membrane H+-ATPase in anoxic elongation of stems in pondweed (Potamogeton distinctus) turions.
abstract: • Pondweed (Potamogeton distinctus) turions can elongate in the absence of O(2). Alcoholic fermentation serves to produce energy for anoxic elongation via the breakdown of starch stored in cells. However, the mechanism of cell growth during anoxic elongation is not fully understood. • Changes in pH, H(+) equivalent and lactate content of the incubation medium were measured during anoxic elongation. The effects of fusicoccin (FC), indole-3-acetic acid (IAA), vanadate, erythrosine B and K(+) channel blockers on anoxic elongation were examined. Cytoplasmic pH and vacuolar pH were measured by (31)P nuclear magnetic resonance (NMR) spectroscopy. • Acidification of the incubation medium occurred during anoxic elongation. The contribution of CO(2) and lactic acid was not sufficient to explain the acidification. FC and IAA enhanced the elongation of stem segments. Vanadate and erythrosine B inhibited anoxic elongation. Acid growth of notched segments was observed. The activity of plasma membrane H(+)-ATPase extracted from pondweed turions was increased slightly in anoxic conditions, but that from pea epicotyls sensitive to anoxic conditions was decreased by incubation in anoxic conditions. Both the cytoplasmic pH and vacuolar pH of pondweed turion cells chased by (32)P NMR spectroscopy were stabilized during a short period < 3 h after anoxic conditions. • We propose that the enhancement of H(+) extrusion by anoxic conditions induces acidification in the apoplast and may contribute to the stabilization of pH in the cytoplasm.
authors.affiliation: Biological Institute, Graduate School of Science, Tohoku University, Sendai, Japan.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Koizumi
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Hara
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Yazaki
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Sakano
authors.forename: Kimiharu
authors.initials: K
authors.lastname: Ishizawa
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D002021:Buffers; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D003470:Culture Media / Q000494:pharmacology; D006027:Glycosides / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D018547:Plant Stems / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D031821:Potamogetonaceae / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D015221:Potassium Channels / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011522:Protons; D013997:Time Factors; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism
chemical_list: D002021:Buffers; D003470:Culture Media; D006027:Glycosides; D007210:Indoleacetic Acids; D015221:Potassium Channels; D011522:Protons; C007808:fusicoccin; C030737:indoleacetic acid; D006180:Proton-Translocating ATPases