Evaluation of Superoxide Anion Level and Membrane Permeability in the Functionally Different Organs of Triticum aestivum L. Exposed to High Temperature and Antimycin A

The impact of antimycin A (AA) as an activator of the alternative respiratory pathway (AP) on the rate of superoxide anion (O^•₂¯) generation and membrane permeability was studied in the functionally different organs of wheat seedlings (Triticum aestivum L.) following short-term and long-term high temperature (HT). The results indicated a significant increase in the O^•₂¯ generating rate in etiolated wheat seedlings and seedlings grown under normal daylight regime following short-term (8%–37%) and long-term (13%– 65%) HT depending on the stage of development. The damages induced by HT were related to the permeability of membranes in the functionally different organs of wheat seedlings. However, our results demonstrated that increase in the O^•₂¯ generating rate in etiolated wheat seedlings was significantly lower following the combined effect of AA and HT, than under stressful conditions without AA. Taken together, our observations show that the induction of AP, provoked by AA, prevents over-reduction of the mitochondrial electron transport chain, alleviating reactive oxygen species formation and protecting the etiolated wheat seedlings against oxidative damage.