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Involvement of plasma membrane H + ‐ATPase in anoxic elongation of stems in pondweed ( Potamogeton distinctus ) turions
Author(s) -
Koizumi Yayoi,
Hara Yoshinao,
Yazaki Yoshiaki,
Sakano Katsuhiro,
Ishizawa Kimiharu
Publication year - 2011
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2010.03605.x
Subject(s) - anoxic waters , elongation , vanadate , biology , fusicoccin , incubation , biochemistry , atpase , chemistry , biophysics , botany , materials science , ultimate tensile strength , metallurgy , ecology , enzyme
Summary• 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.