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Oscillations in H+ and Ca2+ Ion Fluxes around the Elongation Region of Corn Roots and Effects of External pH


Shabala, SN and Newman, IA and Morris, J, Oscillations in H+ and Ca2+ Ion Fluxes around the Elongation Region of Corn Roots and Effects of External pH, Plant Physiology, 113, (1) pp. 111-118. ISSN 0032-0889 (1997) [Refereed Article]

DOI: doi:10.1104/pp.113.1.111


Net fluxes of H + and Ca 2+ around the elongation region of low-salt corn (Zea mays L.) roots were measured using the microelectrode ion flux estimation (MIFE) technique. At pH 5.2 two oscillatory components were found. Fast, 7-min oscillations in H + flux were superimposed on slow oscillations of about 1.5 h. Fast oscillations in Ca 2+ flux showed a strong dependence on the H + oscillations and were normally leading in phase by about 1 to 1.5 min. Both oscillatory components were strongly affected by external pH values. Preincubation for 20 h in buffered pH 4.0 solution suppressed the slow oscillatory component and caused huge H + influxes in the elongation region. The fast oscillations were 8 times larger in amplitude and were slightly lengthened. Preincubation at pH 6.0 did not suppress the rhythmic character of the ion fluxes but it shifted the average H + flux to greater efflux. The fast and slow oscillatory components of H + flux seem to relate to biophysical and biochemical mechanisms of intracellular pH homeostasis, respectively. The origin of the Ca 2+ flux oscillations is discussed in terms of the 'weak acid Donnan Manning' model of cell wall ion exchanges.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Medical and biological physics
Research Field:Biological physics
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Shabala, SN (Professor Sergey Shabala)
UTAS Author:Newman, IA (Dr Ian Newman)
UTAS Author:Morris, J (Dr Morris)
ID Code:10034
Year Published:1997
Web of Science® Times Cited:220
Deposited By:Physics
Deposited On:1997-08-01
Last Modified:2005-06-07

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