Mesophyll K⁺ retention ability has been recently reported as an important component of salinity stress tolerance in wheat. In order to investigate the role of ROS in regulating NaCl^-induced K⁺ efflux in wheat leaf mesophyll, a series of pharmacological experiments was conducted using MV (methyl viologen, superoxide radical inducer), DPI (an inhibitor of NADPH oxidase), H₂O₂ (to mimic apoplastic ROS), and EGCG ((−)-Epigallocatechin gallate, ROS scavenger). Mesophyll pre-treatment with 10 μM MV resulted in a significantly higher NaCl^-induced K⁺ efflux in leaf mesophyll, while 50 μM EGCG pre-treatment alleviated K⁺ leakage under salt stress. No significant change in NaCl^-induced K⁺ efflux in leaf mesophyll was found in specimens pre-treated by H₂O₂ and DPI, compared with the control. The highest NaCl^-induced H⁺ efflux in leaf mesophyll was also found in samples pre-treated with MV, suggesting a futile cycle between increased H⁺-ATPase activity and ROS-induced K⁺ leak. Overall, it is suggested that, under saline stress, K⁺ efflux from wheat mesophyll is mediated predominantly by non-selective cation channels (NSCC) regulated by ROS produced in chloroplasts, at least in bread wheat.

Item Type:	Refereed Article
Keywords:	barley, salinity
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Crop and pasture improvement (incl. selection and breeding)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Grains and seeds
Objective Field:	Barley
UTAS Author:	Wu, H (Mr Honghong Wu)
UTAS Author:	Shabala, L (Associate Professor Lana Shabala)
UTAS Author:	Zhou, M (Professor Meixue Zhou)
UTAS Author:	Shabala, S (Professor Sergey Shabala)
ID Code:	102333
Year Published:	2015
Web of Science® Times Cited:	25
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2015-08-13
Last Modified:	2017-11-06
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