Electrical evidence for turgor inhibition of proton extrusion in sugar beet taproot

• Published in: Plant physiology (Bethesda) Vol. 82; no. 4; pp. 1148 - 1150
• Main Authors: Kinraide, Thomas B., Roger E. Wyse
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.12.1986
• Subjects: Absorption. Translocation of ions and substances. Permeability; Acetates; Acidification; Agronomy. Soil science and plant productions; beta vulgaris; Biological and medical sciences; Cell membranes; Cell physiology; Coleoptiles; Communications; Economic plant physiology; electrical properties; Fundamental and applied biological sciences. Psychology; mannitol; nutricion de las plantas; nutrition des plantes; Nutrition. Photosynthesis. Respiration. Metabolism; Oats; plant nutrition; Plant physiology and development; Plasma membrane and permeation; polaridad; polarite; polarity; propiedades electricas; propriete electrique; Protons; Pumps; racine; raices; roots; Sugar beets; turgencia; turgescence; turgor; Turgor pressure; Membrane pump; Turgor; Dicotyledones; Angiospermae; Plasma membrane; Osmoregulation; Industrial crop; Spermatophyta; Membrane potential; Beta vulgaris; Chenopodiaceae; Proton transport
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.82.4.1148

Sections of sugar beet (Beta vulgaris L.) taproot were incubated in various concentrations of mannitol. At 0.4, 0.6, and 0.8 molar, the membrane electrical potential difference (Em) averaged about -130 millivolts; at 0.2 molar, about -90 millivolts; and at 0 molar, between -60 and -80 millivolts. Additions of 10 millivolts acetate to the incubation solutions (all at pH 5) enhanced the membrane polarity to about -200 millivolts. We conclude from these and previous findings that high turgor inhibits proton extrusion in the sugar beet, but that proton extrusion can be activated in fully turgid tissue by acidification of the cytoplasm. A possible function of this turgor effect may be the control of turgor itself.