Regulation of Cytoplasmic and Vacuolar pH in Maize Root Tips under Different Experimental Conditions 1
AUTOR(ES)
Roberts, Justin K. M.
RESUMO
31P-Nuclear magnetic resonance spectra of perfused maize (Zea mays L., hybrid WW x Br 38) root tips, obtained at 10-minute intervals over 12 hours or longer, indicate that no cytoplasmic or vacuolar pH changes occur in these cells in the presence of 25 millimolar K2SO4, which induces extrusion of 4 to 5 microequivalents H+ per gram per hour. In contrast, hypoxia causes cytoplasmic acidification (0.3-0.6 pH unit) without a detectable change in vacuolar pH. The cytoplasm quickly returns to its original pH on reoxygenation. Dilute NH4OH increases the vacuolar pH more than it does the cytoplasmic pH; after NH4OH is removed, the vacuole recovers its original pH more slowly than does the cytoplasm. The results indicate that regulation of cytoplasmic pH and that of vacuolar pH in plant cells are separate processes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=426414Documentos Relacionados
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