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Ion-specific mechanisms of osmoregulation in bean mesophyll cells

journal contribution
posted on 2023-05-16, 12:05 authored by Sergey ShabalaSergey Shabala, Babourina, OK, Ian NewmanIan Newman
Transient kinetics of net H+,K+, Ca2+, and Cl- fluxes were measured non-invasively, using an ion-selective microelectrode technique, for bean (Vicia faba L.) leaf mesophyll in response to 150 mM mannitol treatment. In a parallel set of experiments, changes in the plasma membrane potential and the total proline content in leaves were monitored. Regardless of the ionic composition of the bath solution, hyperosmotic stress caused a significant increase in the K+ and Cl- uptake into mesophyll cells. At the same time, no significant proline changes were observed for at least 16 h after the onset of stress. Experiments with inhibitors suggested that potassium inward rectifier (KIR) channels, exhibiting mechanosensitive properties and acting as primary receptors of osmotic stress, are likely to be involved. Due to the coupling by membrane potential, changes in K+ and Cl- transport may modify activity of the plasma membrane H+-pump. Such coupling may also be responsible for the mannitol-induced oscillations (period of about 4 min) in net ion fluxes observed in 90% of plants. Calculations show that influx of K+ and Cl- observed in response to hyperosmotic treatment may provide an adequate osmotic adjustment in bean mesophyll, which suggests that the activity of the plasma membrane transporters for these ions should be targeted to improve osmotolerance, at least in this crop.

History

Publication title

Journal of Experimental Botany

Volume

51

Issue

348

Pagination

1243-1253

ISSN

0022-0957

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Oxford University Press

Place of publication

Oxford, England

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences

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