Ionic mechanisms of salt stress perception were investigated by non-invasive measurements of net H+, K+, Ca2+, Na+, and Cl- fluxes from leaf mesophyll of broad bean (Vicia faba L.) plants using vibrating ion-selective microelectrodes (the MIFE technique). Treatment with 90 mM NaCl led to a significant increase in the net K+ efflux and enhanced activity of the plasma membrane H+-pump. Both these events were effectively prevented by high (10 mM) Ca2+ concentrations in the bath. At the same time, no significant difference in the net Na+ flux has been found between low- and high-calcium treatments. It is likely that plasma membrane K+ and H+ transporters, but not the VIC channels, play the key role in the amelioration of negative salt effects by Ca2+ in the bean mesophyll. Experiments with isotonic mannitol application showed that cell ionic responses to hyperosmotic treatment are highly stress-specific. The most striking difference in response was shown by K+ fluxes, which varied from an increased net K+ efflux (NaCl treatment) to a net K+ influx (mannitol treatment). It is concluded that different ionic mechanisms are involved in the perception of the 'ionic' and 'osmotic' components of salt stress.

Item Type:	Refereed Article
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Crop and pasture nutrition
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the environmental sciences
UTAS Author:	Shabala, SN (Professor Sergey Shabala)
ID Code:	18760
Year Published:	2000
Web of Science® Times Cited:	139
Deposited By:	Agricultural Science
Deposited On:	2000-08-01
Last Modified:	2011-11-24
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