Role of nitric oxide and hydrogen peroxide during the salt resistance response.

Ion homeostasis is essential for plant cell resistance to salt stress. Under salt stress, to avoid cellular damage and nutrient deficiency, plant cells need to maintain adequate K nutrition and a favorable K to Na ratio in the cytosol. Recent observations revealed that both nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) act as signaling molecules to regulate K to Na ratio in calluses from Populus euphratica under salt stress. Evidence indicated that NO mediating H(2)O(2) causes salt resistance via the action of plasma membrane H(+)-ATPase but that activity of plasma membrane NADPH oxidase is dependent on NO. Our study demonstrated the signaling transduction pathway. In this addendum, we proposed a testable hypothesis for NO function in regulation of H(2)O(2) mediating salt resistance.