Light-Induced Changes in Cytosolic pH in Leaf Cells of Egeria densa : Measurements with pH-Sensitive Microelectrodes : ENVIRONMENTAL AND STRESS RESPONSES : MEMBRANES AND BIOENERGETICS

元データ 日本植物生理学会

概要

Light-induced changes of cytosolic pH (pH_c) and the plasmalemma potential (E_m) in dark-adapted leaf cells of the aquatic plant, Egeria densa were measured simultaneously with double-barreled pH_c sensitive microelectrodes. Upon illumination, pH_c increased transiently and then decreased to a level that was lower than the original value, while the plasmalemma was greatly hyperpolarized after an initial small depolarization. DCMU inhibited the light-induced changes in both pH_c and E_m. DCMU acted without directly inhibiting the electrogenic proton pump in the plasmalemma since a decrease in pH_c caused by treatment with butyrate (H^+-loading) hyperpolarized the plasmalemma in DCMU-pretreated cells. N.N'-Dicyclohexylcarbodiimide (DCCD) also inhibited the light-induced changes in both pH_c and E~. This result may be explained by direct inhibition of the proton pump in the plasmalemma by DCCD since the decrease in pH_c caused by butyrate did not induce membrane hyperpolarization in DCCD-treated leaf cells. Fusicoccin induced membrane hyperpolarization and slight acidification of the cytosol. DCCD inhibited the fusicoccin-induced changes in both pH_c and E_m. The mechamjsm of the light-induced changes in pH_c is discussed in relation to activities of the proton pump in the plasmalemma and photosynthesis.

著者

Iwasaki Naohiko Dept. Biol. Osaka Med. College
Iwasaki Naohiko Department Of Biology Osaka Medical College
Iwasaki Naohiko Osaka Medical College Department Of Biology
Iwasaki Naohiko Dept. Biol. Osaka Med. Coll.
Tazawa M Fukui Univ. Technol. Fukui Jpn
Tazawa Masashi Department Of Applied Physics And Chemistry Fukui University Of Technology
Okazaki Yoshiji Department of Biology, Faculty of Science, University of Tokyo
Okazaki Yoshiji Department Of Biology Faculty Of Science University Of Tokyo
Tazawa Masashi Departlnent Of Biology Faculty Of Science Osaka University
Okazaki Yoshiji Dept. Biol., Osaka Med. College

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